Solve for x.
x + 27 = 4x
x + 27 = 4x
27 = 3x
9 = x
Define slope.
The slope is a number that describes both the direction and the steepness of the line.
2(2+3)2 = ?
2(2+3)2 = 2(5)2 = 2(25) = 50
Expand the equation y = (x+3)(x-4)
y = x2 + 3x - 4x - 12
y = x2 - x - 12
What is the vertex form?
y = a(x-h)2 + k
Solve for x.
x2 - 3 = 33
x2 - 3 = 33
x2 = 36
x = 6
Define y-intercept.
The y-intercept is the y value at which a line hits the y axis.
In a word problem, is x the dependent or independent variable?
x is the independent variable
Solve 0 = (x+4)(x-2)
x = -4 and x = 2
What happens to our parabola when we change the h value?
How much our parabola shifts left or right.
Solve for x.
3(2x - 5) = 3(x + 10) + 15
3(2x - 5) = 3(x + 10) + 15
6x - 15 = 3x +45
3x = 60
x = 20
What is the equation of a line? Describe it.
y = mx + b
m is the slope
b is the y-intercept
Using the whiteboard, draw the graph for y = -(x-4)2
There is only one x-intercept at x=4.
The parabola is facing down.
What are two methods you can use to solve
0 = x2+8x+16 ?
2. Quadratic Formula
What happens to our parabola when we change our k value?
Our parabola shifts up or down.
Solve for x.
(-2x)2 = 36
(-2x)2 = 36
4x2 = 36
x2 = 9
x = 3
Using the whiteboard function, graph y = 2/3x - 4.
The slope is 2/3
The y-intercept is -4
The monkey has 3 bananas. Everyday the monkey collects 2 more bananas. How many bananas does the monkey have after a week of collecting bananas?
y = 2(7) + 3
y = 17 bananas
Factor the equation y = x2 + x - 30.
y = (x+6)(x-5)
How do you find the vertex of a parabola given the equation y = a(x-h)2+k
The vertex is (h,k).
Solve for x.
x2 - 4x + 2 = 2x2 - 2(2x+7)
x2 - 4x + 2 = 2x2 - 2(2x+7)
x2 - 4x + 2 = 2x2 - 4x - 14
16 = x2
4 = x
How do you find the slope if you are given a graph of a line?
Pick two points and calculate rise/run.
What is the quadratic formula?
1. Find the x-intercept(s)
2. Use the form y = (x+_)(x+_)
3. Use the foil method to get y = ax2 + bx + c
What happens when you change the a value of a parabola? Hint: two things happen
1. The positive/negative sign determines if our parabola is facing up or down
2. If |a| < 1, our parabola is wider
If |a| > 1, our parabola is skinnier