Question

If f(x)=2x−3 and g(x)=4x+5, what is (f⋅g)(x)?

A)(f⋅g)(x)=8x−15
B)(f⋅g)(x)=6x+2
C)(f⋅g)(x)=8x2+22x−15
D)(f⋅g)(x)=8x2−2x−15

Answer 1

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Answer:

D) (f⋅g)(x)=8x2−2x−15

Explanation:

(f·g)(x) = f(x)·g(x) = (2x -3)(4x +5) = 2x(4x +5) -3(4x +5)

= 8x² +10x -12x -15

(f·g)(x) = 8x² -2x -15