Hello,
B:
2px+4py-8qx-16qy=2p(x+2y)-8p(x+2y)
=(x+2y)(2p-8q)=2(x+2y)(p-4q)
C:
30y²-33yz-18z²=3(5y+2z)(2y-3z)
Since
Let's assume u=y/z
30y²-33yz-18z²=3(10y²-11yz-6z²)
=3z²((10(y/z)²-11(y/z)-6)
=3z²(10u²-11u-6)
=3z²(5u+2)(2u-3)
=3z²*(5y/z+2)(2y/z-3)=3z²(5y+2z)(2y-3z)/z²
=3(5y+2z)(2y-3z)
