Question

What is the equation of the following line written in slope intercept form? (-5,-1)

Answer 1

Answer:

$\large\boxed{y=-\dfrac{2}{3}x-\dfrac{13}{3}}$

Step-by-step explanation:

The slope-intercept form of an equation of a line:

$y=mx+b$

m - slope

b - y-intercept

The formula of a slope:

$m=\dfrac{y_2-y_1}{x_2-x_1}$

From the graph we have two points (-5, -1) and (-2, -3).

Look at the picture.

Calculate the slope:

$m=\dfrac{-3-(-1)}{-2-(-5)}=\dfrac{-2}{3}=-\dfrac{2}{3}$

Put it to the equation in slope-intercept form:

$y=-\dfrac{2}{3}x+b$

We can't read the y-intercept from the graph. Therefore put the coordinates of the point (-5, -1) to the equation and calculate b:

$-1=-\dfrac{2}{3}(-5)+b$

$-1=\dfrac{10}{3}+b$         subtract 10/3 from both sides

$-\dfrac{3}{3}-\dfrac{10}{3}=b\to b=-\dfrac{13}{3}$

Finally:

$y=-\dfrac{2}{3}x-\dfrac{13}{3}$