If h(x) = x – 7 and g(x) = x2, which expression is equivalent to mc022-1.jpg?

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the full question is as follow:

If h(x) = x – 7 and g(x) = x2, which expression is equivalent to (g*h)(5)?

A (5 – 7)2,
B (5)2 – 7,
C (5)2(5 – 7),
D (5 – 7)x2

first, the main rule of the product between two functions g and h is

g(x)*h(x)= (g*h)(x)

h(x) = x – 7 and g(x)=x², so (g*h)(x)= g(x)*h(x)=[x²][x – 7 ]= x^3 -7x²

(g*h)(x)= x^3 -7x², therefore, (g*h)(5)= 5^3 -7*5² = -50 = (5)2(5 – 7)

finally, the answer is C (5)2(5 – 7), 

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