Question

The equation of the line that goes through the points ( − 3 , − 9 ) and ( − 6 , − 3 ) can be written in the form y = m x + b

Answer 1

Answer:

$y=-2x-15$

Step-by-step explanation:

$y=mx+b$.

m is the slope of the line. To find it we can do $\frac{dy}{dx}$ which is the difference between the y-coordinates divided by the difference between the x-coordinates.

So: $\frac{dy}{dx} =\frac{-9-(-3)}{-3-(-6)} =\frac{-6}{3} =-2$. Now we have the slope, let's input a set of coordinates into the equation so that we can find the constant $b$.

$-9=-2(-3)+b$

$b=-15$ - Re-arranging to get b

Now re-write the equation as we have the constants.

$y=-2x-15$