Question

Find an equation of the line passing through the pair of points. Write the equation in the form Ax+By=C

(-7,2), (-8,-9)

Answer 1

11x - y = -79

Explanation:

The standard form of an equation of a line:

`Ax+By=C`

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

`y-y_1=m(x-x_1)`

m - slope

(x₁, y₁) - point

We have the points (-7, 2) and (-8, -9). Substitute:

`m=(-9-2)/(-8-(-7))=(-11)/(-1)=11`

`y-2=11(x-(-7))\\\\y-2=11(x+7)`

Convert to the standard form:

`y-2=11(x+7)` use the distributive property a(b + c) = ab + ac

`y-2=11x+77` add 2 to both sides

`y=11x+79` subtract 11x from both sides

`-11x+y=79` change the signs

`11x-y=-79`