Question

How do you write an equation of a line given (–1, –3) and (4, 1)?

Answer 1

`y=4/5 x - 11/5`

Explanation:

First find slope of the line: `m=(y_2 - y_1)/(x_2 - x_1)` = `4/5`

Then substitute slope and x and y coordinates from one of the points into general equation `y=mx+b`. This gives `1= (4/5)4 + b`. Solve for b gives `b= - 11/5`.