Question

What is the equation in point-slope form of the line passing through (2, 5) and (–1, 8)?

Answer 1

The answer is: `y=-x+7`.

Using the formula that gives the equation of a line, given two points `A` and `B`:

`(y-y_A)/(y_B-y_A)=(x-x_A)/(x_B-x_A)`,

so:

`(y-5)/(8-5)=(x-2)/(-1-2)rArr(y-5)/3=(x-2)/-3rArry-5=-x+2rArr`

`y=-x+7`.