Answer: Choice D
-3x^5 - 7x^3 + 18x^2 + 42
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Work Shown:
(3x^2 + 7)(6 - x^3)
y(6 - x^3) ........ let y = 3x^2+7
y*6 - y*x^3 ..... distribute
6y - x^3y
6( y ) - x^3( y )
6( 3x^2+7 ) - x^3( 3x^2+7 ) ..... plug in y = 3x^2+7
6*3x^2 + 6*7 - x^3*3x^2 - x^3*7 .... distribute twice more
18x^2 + 42 - 3x^5 - 7x^3
-3x^5 - 7x^3 + 18x^2 + 42