Firstly, you have to know what FOIL stands for.
F= first
O= outside
I= inside
L= last
So to solve you start with the first two numbers of each of the equations in parentheses (5r and r) which will equal 5r^2
outside is 5r and 2 which equals 10r
inside is 13 and r which equals 13r
last is 13 and 2 which is 26
then you have 5r^2, 10r, 13r, and 26
add common characters and you'll have 5r^2+23r+26
