Question

How do you simplify `(2r -5)(r + 10)`?

Answer 1

`2r^2+15r-50`

Explanation:

To do this we use a technique called FOIL. It stands for firsts, outers, inners, and lasts.

`(2r- 5)(r+10)`
Here, `2r` and `r` are the firsts, `2r` and `10` are outers, `-5` and `r` are inners, and `-5` and `10` are lasts. Solving the problem only requires that we multiply these pairs together and combine them.

`(2r-5)(r+10)`
`(2r*r)+(2r*10)+(-5*r)+(-5*10)`
`2r^2+20r-5r-50`
`2r^2+15r-50`