Question

Which equation represents the line that passes through the points (-3;7) and (9,-1)

Answer 1

`y = - (2)/(3) x + 5`

Explanation:

`y = mx + b`

finding the slope m of the line using the above points

`m = (y2 - y1)/(x2 - x1) = \\ ( - 1 - 7)/(9 - - 3) = ( - 8)/(9 + 3) = - (8)/(12) = - (2)/(3)`

substitute the slope and one of the points into the y-intercept form to solve for b

`y = mx + b \\ 7 = - (2)/(3) ( - 3) + b \\ 7 = (6)/(3) + b \\ 7 - 2 = b \\ b = 5`

therefore the answer to the question is

`y = - (2)/(3) x + 5`