Question

Write the product as a trinomial.

Answer 1

We'll use the FOIL method to multiply the factors.

FOIL
First, Outside, Inside, Last

Multiply the first terms, then the outside terms, then the inside terms, then the last terms.

First
(2r – 5)(r + 10) 

$2r \times r = 2r^2$

Outside
(2r – 5)(r + 10) 

$2r \times 10 = 20r$

Inside
(2r – 5)(r + 10) 

$-5 \times r = -5r$

Last
(2r – 5)(r + 10) 

$-5 \times 10 = -50$

The trinomial should now look like this:

$2r^2 + 20r - 5r - 50$

Combine like terms:

$20r - 5r = 15r$

The following trinomial will be your answer:

$\boxed{2r^2 + 15r - 50}$

Answer 2

First we multiply 2r*r and it gives us $2r^{2}$. 

Then -5r, + 20r = 15r

Then -5*10 gives us -50.

So the answer is: $2r^{2}+15r-50$