Let f(x) = 3x^2 + 5x – 7 and g(x) = –x^2 + 2x + 1. (g-f) (3)

Mathematics · Middle School · Thu Feb 04 2021

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Given the function:

f(x) = 3x^2+ 5x - 7

g(x) = -x^2 + 2x + 1

Determine g - f (3)

Solution:

In order to determine g - f ( 3), we simply need to equate the two functions into one equation separated by a minus sign, whereas 3 is substituted to the value of x, to each function f(x) and g(x)

g - f ( 3)= (- (3)^2 + 2(3) + 1 ) - (3(3)^2 + 5(3) - 7)

g - f ( 3)= (- 9 + 6 + 1 ) - (3(9) + 15 - 7)   

g - f ( 3)= (- 2) - (27 + 15 - 7)   

g - f ( 3)= (- 2) - (35)

g - f ( 3)= - 2 - 35   

g - f (3) = -37

Final answer:

g - f (3) = -37