Question 659726
Starting with (r3 + r2)^2
(r3 + r2)(r3 + r2)
Use FOIL - first, outside, inside, last
9r^2 + 6r^2 + 6r^2 + 4r^2
25r^2
Alternatively
(r3 + r2) is 5r, so (5r)^2 = 25r^2