^algebra^
(3x2 + 8x)(2x − 2)
=3x²(2x-2)
=6x³ - 6x²
+8x(2x - 2)
=16x² - 16x
put it all together
=6x³ - 6x² + 16x² - 16x
group according to variables, then count
6x³ + (-6x² + 16x²) - 16x
=6x³ + (+10x²) - 16x
=6x³ + 10x² - 16x
FINALLY FOUND, MODERATOR!