4.1- Slope Intercept Form & 4.2 - Point Slope Form

4.1- Slope Intercept Form &

4.2 - Point Slope Form

Slope-intercept Form

• If you are given the slope and the y-intercept use slope-intercept form to write the equation of the line

• m = slope

• b = y-intercept

• if a point has an x-value of 0, the y-value is the y-intercept: (0, b)

Multiple Choice

What is the equation of a line with a slope of 2 and a y-intercept of -5?

• y = 5x - 2

• y = 2x - 5

• y = -2x - 5

• y = 2x + 5

Multiple Choice

What is the equation for the line with a slope of 7 and passes through (0,1)?

• y = -7x + 1
• y = 7x + 1
• y = -1/7x - 1
• y = -1/7x + 1

Given two points:

• If you are given two points you can find the slope using the slope formula and plug the slope in for m.

• Then determine which point is the y-intercept to find b.

Multiple Choice

Given the two points: (0, 6) and (6,18), write the equation of the line.

• y = 2x + 6

• y = 1/2x + 6

• y = 1/3x + 6

• y = 3x + 6

Given a point (not the y-intercept) and the slope

• Plug in the slope for m

• Label the point (x₁, y₁) and plug in the values for x₁ and y₁

• Then you have written the equation in point-slope form

Multiple Choice

Write the equation of the line

in Point-Slope form that goes through

the point (10,5) and has a slope of -3

• y - 5 = -3(x - 10)

• y= -3x + 35

• y + 5= -3(x + 10)

• y= -3x - 35

Multiple Choice

Write the equation in point-slope form

of the line that passes through the point

(4, -7) and has a slope of -1/4.

• y + 7 = -1/4(x - 4)

• y - 4 = -1/4(x + 7)

• y + 7 = 4(x - 4)

• y - 7 = -1/4(x - 4)

Point-slope form to Slope-intercept form

• Step 1: Write the equation in point slope form if not already

• Step 2: Distribute (multiply) the slope inside the parenthesis

• Step 3: Undo what is happening to y to get y by itself on the left side

Multiple Choice

Write an equation  
m = 5 through (-1, -3)

• y = 5x + 2
• y = -5x - 5
• y = -5x + 2
• y = 2x - 5

Multiple Choice

Write an equation

m = 1/3 through (4, 4)

• y = -1/3x + 8/3

• y = 8/3x - 1/3

• y = 8/3x + 1/3

• y = 1/3x + 8/3

Multiple Choice

Find the slope intercept form given a line with a slope of 4 going through the point (3,8)

• y=-4x-4

• y=3x-8

• y=4x-4

• y=4x+20

Multiple Choice

Write an equation  
m = 5/4 through (-4, -3)

• y = 5/4x +2
• y = -5/4x + 2
• y = 2x - 5/4
• y = 3/4x + 2