Question 60353
a. 5r^2+15rs-2rs-6s^2 
(5r)(r+3s)-(2s)(r+3s)
(5r-2s)(r+3s)
.
b. 10p^3-2p^2q^2-5pq+q^3
(2p^2)(5p-q^2)-(q)(5p-q^2)
(2p^2-q)(5p-q^2)