Write an equation in slope-intercept form that satisfies the condition: (9, 0); m = -3

Answer 1

Slope intercept form is probably the most common way to write linear equations, which looks like this:

y = mx + b, where y = dependent variable, or output

m = slope

x = independent variable, or input

b = y intercept

There are several ways to approach this problem. Because you're given the coordinate of one point, and the slope, I would start by first writing your equation in point slope form, which looks like this:

y - y₁ = m(x - x₁), where y = dependent variable, or output

y₁ = y coordinate in your given point

m = slope

x = independent variable, or input

x₁ = x coordinate in your given point

For this problem,

m = -3

x₁ = 9

y₁ = 0

Plug everything in and solve for y to get your equation in slope intercept form:

y - y₁ = m(x - x₁)

y - 0 = -3(x - 9)

y = -3x + 27

Answer 2

Slope intercept form is y = m(x) + b; where m is the slope and b is the y intercept. Since you were given the slope, just plug in (-3) for m above, and put in the x and y value (9,0) to solve for b. Doing that you get:

0 = (-3)(9) + b solve for b and you find b = 27, so you plug that back into the equation y = (-3)x +27 and you are done.

y = -3x + 27