Algebra Flashcards
Identities
(a + b)2
a2 + 2ab + b2
Identities
(a-b)3
a3 - 3a2b + 3ab2 - b3
Identities
a2 - b2
(a + b) (a - b)
Exponent Rules
X-a
1
xa
Exponent Rules
(xa)(xb)
xa+b
Exponent Rules
xa
xb
xa-b
1
xb-a
(if negative)
Exponent Rules
x0
1
Exponent Rules
00
not defined
Exponent Rules
(xa)(ya)
(xy)a
Exponent Rules
(x/y)a
xa/ya
Exponent Rules
(xa)b
xab
2 ways to solve linear equations with 2 variables
Substitution
Elimination
Quadratic equation form
ax2 + bx + c
Quadratic formula
x= -b+/- √(b2- 4ac)
2a
√-x
undefined
Factoring a quad equation when answer = 0
Factor into parentheses and set each as equal to zero since the answer is zero
Yields two possible answers
Solution set
all the values that can make an inequality true
Equivalent inequalities
have the same solution set
Inequalities:
multiplying or dividing by a negative
Reverse direction of the symbol
State inequality solution x >/= 4
all real numbers greater than or equal to 4
Distance formula
d = rt
rate
time
Domain of a function
all permissable values of the variable
Simple interest formula
V = P R T
Value
Principle
rate % in decimal form
time (years)
Compound interest formula (annual)
V = P (1 + r/100)t
Compound interest formula (other time intervals)
V = P(1+ r/100n)nt
n times per year
t years
P(x,y) and P1(x,-y)
symmetric/reflect about the x axis
P(x,y) and Pn(-x,y)
Symmetric/reflect about the y axis
P(x,y) and Pm(-x, -y)
symmetric/reflect about the origin
How to find the distance between two points using the Pythagorean theorem
- Construct a right triangle
- Fing lengths of shorter sides (subtract whichever numbers differ, x1-x2 or y1-y2)
- Apply theorem
What does the graph of an equation (with 2 vars) show
all points whose ordered pairs satisfy the equation
How to find the slope of a line that passes through 2 points
Q(x1,y1) and R(x2,y2)
y2-y1 / x2-x1 = m
rise/run
slope = 0
horizontal line, no rise
equation for horizontal lines
y=b
vertical slopes
equation
not defined
x = a (x-intercept)
When slopes are equal, the lines are
parallel
When one slope is the negative reciprocal of the other (i.e 2 and -1/2)
the lines are perpendicular to each other
How to find the x-intercept from a y=mx+b equation
set y=0
solve for x
how to find a graph solution with a system of equations
solve for y in terms of x
graph
solution is where the 2 lines intersect
How to find a graph solution for a system of linear inequalities
solve for y in terms of x
shade regions
solution of the set are all points that fall in shaded regions
describe line y = x
passes through origin
slope of 1
makes 45 degree angle with each axis
how points (a, b) and (b, a) relate
reflect across the line y=x
Describe what a quadratic equation looks like on a graph
parabola
symmetric about line through vertex
the two x-intercepts are equidistant from the vertex line
ax2 + bx + c = 0
if a is positive…
if a is negative…
parabola opens upward and vertex is lowest point
opens down and vertex is highest
(x - a)2 + (y - b)2 = r2 form
circle
center is (a, b)
radius is r
Graphing functions
x is input
y= f(x)
f(x) = mx + b….y = mx + b
how to find the intersection points of two functions
- set the functions as equal to each other [g(x) = f(x)]
- Solve for x with quadtractic equation form
- Quadratic formula - results are x coordinates
- Plug in each result into one of the functions to find coresponding y coordinates
Graph of a function of an absolute value
V-shaped
y= x and y= -x
join at the origin
Graph of functions with square root/ negative square root
half parabolas
right and left half reflections of y= x2 about the y= x line
y = -h(x) and y = h(x)
-h(x) is the reflection of h(x) about the x-axis
h(x) + c
h(x) shifts up c units
h(x) - c
h(x) shifts down c units
h(x+c)
h(x) shifts left c units
h(x-c)
h(x) shifts right c units
ch(x)
c > 1
h(x) stretched vertically by a factor of c
ch(x)
0 < c < 1
h(x) shrunk vertically by factor of c
Formula for circles on xy plane
(x - a)2 + (y - b)2 = r2
Xa/b
b√xa