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

1 Answer
Sep 22, 2015

Answer:

#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#