1. Find Slope and Y Intercept from an Equation

2. What is Slope-Intercept Form of an Equation?
Slope Intercept Form: y = mx + b
The equation y = mx + b includes:
the input (x), the independent variable
the output (y), the dependent variable
m is the rate of change, the “slope”
b is the y-intercept, the “starting value” when x=0
This format makes it easy to graph the equation.

3. Write the equation of a line whose slope is -2 and y-intercept is (0, 3).
Start by writing y = mx + b.
m is slope and b is y-intercept
Substitute “-2” for m.
Substitute “3” for b.
The equation is y = -2x + 3.

4. What is the slope of the line represented by each equation?
y = -3x + 7.5
y = 1/3 x – 14
y = -27x
Make sure equation is in slope-intercept form
y=mx+b order y = -3x + 7.5
slope m = -3
b = y-intercept (0, 7.5) slope m = 1/3
b = y-intercept (0,-14) slope m = -27
b = 0 y-intercept (0,0)

5. What is the slope of the line represented by each equation?
What if it isn’t already written in slope-intercept form?
*Re-write in slope-intercept form*
(y=mx+b order)
1. Combine all x’s together on right of equal sign
(or move over to the right side if x’s start on left by inverse operations (add or sub)
2. Then isolate y on left of equal sign using inverse operations
(divide away the 2 to get y all alone)
3. When it’s in y=mx+b order, the m=slope and the b=y intercept
2y = 7x + 5 – 3x 2y = 7x + 5 – 3x 2y = 4x + 5 2y = 4x y = 2x + 2.5
Slope m = 2 and b=2.5 y-intercept (0,2.5)

6. What is the slope of the line represented by each equation?
3x - 8y = 24 3x - 8y = 24 -3x -3x -8y = -3x y = -3x y = 3/8 x - 3
*Re-write in slope-intercept form*
(y=mx+b order)
1. Combine all x’s on right or
move over to the right side if x’s start on left by inverse operations (add or sub)
*note: you can’t combine -3x with 24 so list them separately!
2. Then isolate y on left of equal sign using inverse operations
(divide away the -8 to get y all alone)
3. When it’s in y=mx+b order, the m=slope and the b=y intercept
Slope m = 3/8 and b= -3 y-intercept (0,-3)