given a system of equations, what does it mean when you solve and get an equation that is always true?
Front
the equations are all for the same line
Back
How do quartiles divide a list?
Front
Q1, median, Q3, divide a list into 4 equal (in terms of number of points) groups
Back
square of a difference
Front
(a-b)^2 = a^2 - 2ab + b^2
Back
concentration
Front
amount of solute/total amount of solution (not amount of solute over amount of water)
Back
Sum of Angles in a Regular Polygon
Front
find the sum of the angles by using (n-2)180, then divide by n to find the measure of each individual angle
Back
Circumference of a circle
Front
C=2πr
C=πd
Back
Formula for arc length
Front
arc length/2πr = angle/360
Back
solving most quadratics on GRE
Front
1) get everything equal to zero
2) divide by any GCF
3)factor
4) use zero product property to create two linear equations equal to zero, solve
Back
The sum of the angles in a quadrilateral is
Front
360°
Back
Percent of a population between each standard deviation, from -2SD to +2SD
Front
2% -2SD 14% -1SD 34% mean 34% +1SD 14% +2SD 2%
Back
Power Rule (to raise a power to a power)
Front
multiply the exponents
Back
"or" or "is" in word problems
Front
=
Back
Parallelogram Properties
Front
1) opposite sides are parallell.
2) opposite sides are congruent.
3) opposite angles are congruent.
4) consequtive angles are supplementary.
5) diagonals bisect each other.
Back
Volume of a rectangular solid
Front
(length)(width)(height)
Back
A is 50 more than B
Front
A=B+50
Back
measure of inscribed angle
Front
1/2 the measure of the intercepted arc
Back
30-60-90 triangle (half an equilateral triangle)
Front
1:√3:2
Back
Fraction Exponent
Front
The denominator becomes the root, the numerator becomes the power
Back
sum of angles in n sides polygon
Front
(n-20x180
Back
difference of two squares
Front
a² - b² = (a + b)(a - b)
Back
Area of a square
Front
A=s²
Back
Pythagorean triplits
Front
(3,4,5)(5,12,13)(8,15,17)(7,24,25)
Back
volume of cube
Front
V=s^3
Back
isosceles triangle
Front
equal bases, opposite angles equal
Back
velocity of objects moving in the same direction
Front
subtract, the velocity is the rate at which the gap is closing if they are growing closer, the velocity is the rate at which the gap is growing if they are moving further apart
Back
sum of squares
Front
(a+b)^2 = a^2+2ab+b^2
Back
how do you find the 1st and 3rd quartile?
Front
they are the medians of each half of the list on either side of the median
Back
Average velocity
Front
total distance/total time (add distances and times from each leg)
Back
A is 50 less than B
Front
A=B-50
Back
Surface area of a rectangular solid
Front
2lw + 2wh + 2lh
Back
Area of a trapezoid
Front
A=1/2(b1+b2)h
Back
interquartile range
Front
The difference between the upper and lower quartiles. the middle 50 percent of a population
Back
degree of an angle inscribed in a semicircle
Front
90
Back
Area of a triangle
Front
A=1/2bh
Back
Product Rule (to multiply exponents)
Front
Keep the base and add the powers
Back
isosceles right triangle
Front
sides = 1:1:√2
angles = 45:45:90
Back
equilateral triangle
Front
all equal sides, all 60 degree angles
Back
trapezoid
Front
A quadrilateral with exactly one pair of parallel sides
Back
Area of a sector
Front
area of sector/πr² = angle/360
Back
rectangle
Front
all 90 degree angles + big four
Back
Negative Exponents
Front
any nonzero number raised to a negative power equals its reciprocal raised to the opposite positive power
Back
symmetrical trapezoid
Front
equal legs; equal angles on each side; equal diagonals
Back
what do the lines on a box plot represent?
Front
the max, min, and three quartile numbers (Q1, median, Q3)
Back
Quotient Rule (to divide exponents)
Front
to divide, keep the base and subtract the powers
Back
Velocity of objects moving in opposite directions
Front
add, if they are going towards each other the velocity is the velocity at which the gap is closing, if they are moving away from each other the velocity is the rate at which the gap is growing
Back
Section 2
(50 cards)
how to get the x or y intercept from a line's equation
Front
plug 0 in for y to get the x intercept, and for x to get the y intercept
Back
Probability that either A or B will happen?
ex, if the probability that A occurs is is .4, the probability either of them occur is .6, and the probability they both occur is .25, what is the probability that B occurs?
Front
peither a or b =pA + pB - (pB and B)
The probability that either will occur individually minus the probability that they both do
ex.
.6 = 0.4 + pb - 0.25
pB=0.15
Back
Method for problems where members of a group are placed into two different kinds of categories (i.e. age and city of origin)
Front
double helix method: each one category is spread over columns, one over rows, plus a totals row and column
Back
the amount of possible combinations when choosing a group (in any order) from a larger group
Front
nCr
n = number in big group
r = number in small group
nCr = n!/r1
Back
two main causes for an undefined (not real) solution?
Front
the square root of a negative and division by 0
Back
if b is between 0 and 1, is the square root of b greater than or less than b?
Front
yes
Back
how to count the number of factors of a large number
for odds?
evens?
Front
to find the number of factors of N:
1) find the prime factorization of N
2) list the exponents of primes
3)add one to each = a new list
4) product of new list = # of factors
for odd factors, just discount the factors of 2 in the first list
for even, find the total number and subtract the number of odds
Back
standard deviation
Front
a computed measure of how much scores vary around the mean score
Back
given a system of equations, what does it mean when you solve and get an equation that is never true?
Front
the equations are parallel
Back
how to tell if a number is divisible by 3
Front
if the sum of its digits is divisible by 3
Back
solving absolute value equation
Front
-isolate expression in absolute value
-set it equal to the positive and negative of whatever is on the other side of the equation
-solve both
-check for extraneous solutions
Back
how to take the root of a root
ex. cube root of a square root
Front
multiply roots
answer 6th root
Back
finding the equation of a line given a single point and the slope?
Front
plug the point in for x and y, plug in the intercept, solve for b (the intercept)
Back
if b > 1, then is the square root of b greater than or less than b?
Front
less
Back
the nth term of any arithmetic sequence
Front
a of n = a of 1 + d (n-1), where d is the number that is added each term and a is the remained when any term is divided by d
Back
adding inequalities
Front
we can add inequalities when the inequality signs are the same
Back
Slopes of Perpendicular Lines
Front
Slopes are negative reciprocals or each other
Back
on a coordinate plane, the equation of a circle with center 0,0
Front
x^2 + y^2 = r^2
Back
equation of y axis?
Front
x = 0
Back
Raising a root to a power
Front
When raising a root to another power, simply convert the root to power form and multiply the exponents.
For example:
(√a) to 2 = (a½) to 2 = a (½·2) = a to 1 = a
roots and powers of the same level cancel each other out, leaving only the base.
∜a to 4 = a
Back
finding the distance between two points on the coordinate plane
Front
slope triangle to find rise and run, then Pythagorean theorem (leg^2 + leg^2 = hypotenuse^2). Hypotenuse = distance
Back
Is zero an integer?
Front
yes
Back
when checking a solution to an absolute value equation, what happens if the absolute value of an expression turns out to be equal to a negative number?
Front
this means that the solution is an extraneous solution. An absolute value cannot be equal to a negative number
Back
how to tell if a number is divisible by 9
Front
if the sum of its digits is divisible by 9
Back
multiplication and division in an inequality?
Front
multiplying and dividing by a positive number works the same as with equations
multiplying or dividing by a negative number reverses the order of the inequality
Back
as compounding period decreases, what happens to amount of interest earned?
Front
it increases
Back
Compound interest formula (non annual compounding)
Front
A=(P/n)(r^yn)
A=Amount
P=Principal
r=Multiplier
y=years
n = how many times in a year the the interest is compounded (ex. compounded quarterly, n = 4)
Back
choosing a combination out of a larger group (when order does not matter)
ex. J is allowed to invite 3 friends on a camping trip. if J has th10 friends, how many ways can she invite 3 of them?
Front
n!/r!(n-r)!
ex answer:
10!/3!(10-3)!
120
Back
how to add a sequence of evenly spaced integers
Front
pair the numbers by first and last to produce pairs of a constant sum. then multiply by the number of pairs.
[n(n+1)]/2
Back
Precent increase formula
Front
[(new value-original value)/original value] x 100
Back
slope-intercept form
Front
y=mx+b, where m is the slope and b is the y-intercept of the line.
Back
Work Rate with multiple workers
Front
Work = Individual Rate x Number of Workers x Time
Back
when should you include the negative square root?
Front
if the square root sign is written by the test maker, consider positive roots only
Back
equation of vertical line?
Front
x = k (where k is the x intercept)
Back
how to tell if a number is divisible by 6
Front
it must be divisible by 2 and 3
Back
general form of horizontal line?
Front
y=k (where k is the y intercept, or the "height" of the line )
Back
how to get ride of roots in the denominator?
Front
if the fraction has a single root in the denominator, we rationalize by multiplying by that root over itself.
if the denominator of the fraction contains addition or subtraction involving a radical expression, we multiple the conjugate of the denominator over itself (use the difference of two squares to get a square minus a square
Back
Units Digit Question
Front
1) Look for repeating pattern, usually 4
2) Figure out where the pattern will be at the desired power
*Only need to consider single digit product*
use the points to find the slope, plug the slope into slope intercept form as well as one of the points, then solve for b
Back
1/ (a/b) = ?
Front
b/a
Back
equation of x axis?
Front
y = 0
Back
multiplying and dividing inequalities?
Front
can't do it
Back
addition and subtraction in an inequality?
Front
the same as with equations
Back
how to solve proportional reasoning questions when working with formulas (given a formula, told some variables will be multiplied by some number, asked what some variable would be multiplied by as a result)
Front
set every variable equal to one, then make the changes described by the questions
potential results when solving a system of two equations with two unknowns
Front
one solution (intersect point), infinite solutions (same line), no solutions (parallel line)
Back
Volume of a cylinder
Front
V = πr^2h
Back
Subtracting inequalities
Front
we can subtract inequalities when the inequality signs are in the opposite directions (the resultant inequality follows the sign of the initial inequality
Back
Section 3
(2 cards)
combinations of side lengths and angles that are enough to determine everything else about the triangle
Front
side side side
side angle side
angle side angle
angle angle side