Question

A line passes through the points (–12, 40) and (8, –20). The equation of this line can be expressed as y = ax + b, where a and b are integers. What are the values of a and b?

Answer 1

`y=-3x+4`

Explanation:

`a` is the gradient of that line and can be calculated with any two points on that very line.
`a=(y_1-y_2)/(x_1-x_2)`
`a=(40-(-20))/(-12-8)=60/-20=-3`

`y=-3x+b`

We can find b by substuting any of the two points. (I picked `p_1`)

`40=-3*(-12)+b`
`40=36+b|-36`
`4=b`