Question

The slope formula can be used to find the slope, m, of a line with points (L1, y1) and (22, 42).

Y2 - Yi
22 - 21
m
Which is an equivalent equation?
O Y1 = -m (22 – x1) + y2
yı = -m (x2 – 21) – Y2
Oyı = m (22 – 21) + y2
Oyı = m (22 – 21) – Y2

Answer 1

A.
`y_1 = -m(x_2 - x_1) + y_2`

Explanation:

Given, slope formula =
`m = (y_2 - y_1)/(x_2 - x_1)`

To find an equivalent equation, let's make
`y_1` the subject of the formula.

`m = (y_2 - y_1)/(x_2 - x_1)`

Cross multiply

`1(y_2 - y_1) = m(x_2 -x_1)`

`y_2 - y_1 = m(x_2 - x_1)`

Subtract
`y_2` from both sides

`y_2 - y_1 - y_2 = m(x_2 -x_1) - y_2`

`- y_1 = m(x_2 - x_1) - y_2`

Divide both sides by -1

`(- y_1)/(-1) = (m(x_2 -x_1) - y_2)/(-1)`

`y_1 = -m(x_2 - x_1) + y_2`