(-9,1) m=-1/3 slope intercept form

Question

For the following problem, the slope and one point on a line are given. Use the point-slope form to

 find the equation of the line. Write your answer in slope-intercept form.

(−9, 1) m = − 1/3

 

Answer 1

Given line slope m = -1/3

point (-9,1)

equation of the line y-y1 = m(x-x1)

y-1 =-1/3(x-(-9))

y-1 = -1/3(x+9)

Cross multiplying

(y-1)3 = -1(x+9)

3y-3 = -x-9

Add 3 to each side.

3y-3+3 = -x-9+3

3y = -x-6

Divide by 3 to each side.

3y/3 = (-x-6)/3

y = -x/3-6/3

y = -x/3-2

y =(-1/3)x-2

Slope intercept form of the line y = (-1/3)x-2

Comments

The point - slope - form of a line equation is y - y₁ = m(x - x₁).

Slope - intercept - form of a line equation is y = mx + b.