Question

What is the equation of a line going through points (-15,70) and (5,10)

Answer 1

Simple....

you have:

(-15,70) and (5,10)

Using-->>

$\frac{ y_{1} -y_{2} }{ x_{1}- x_{2} }$

$\frac{70-10}{-15-5} = \frac{60}{-20} = -3$

Using y=mx+b...and any of the coordinates....

70= -3(-15)+b

70=45+b

70=45+b
-45  -45

25=b

y=-3x+25

Thus,your answer.