# How do you find a standard form equation for the line with x-intercept 4 with a slope -3?

May 15, 2016

y = - 3x + 12

#### Explanation:

The equation of a line can be expressed in the form$\textcolor{red}{| \overline{\underline{\textcolor{w h i t e}{\frac{a}{a}} \textcolor{b l a c k}{y = m x + b} \textcolor{w h i t e}{\frac{a}{a}} |}}}$
where m represents the slope and b, the y-intercept.

The coordinates of the point with x-intercept = 4 are (4 ,0)

Here the slope = - 3 and so the partial equation is y = -3x + b

To find b ,substitue (4 ,0) into the partial equation.

x = 4 , y = 0 : - 12 + b = 0 → b = 12

thus the full equation is : y = -3x + 12
graph{-3x+12 [-40, 40, -20, 20]}