Answer:
f(x) = -60 is your answer
Step-by-step explanation:
Plug in 3 for x
f(x) = 5x² - 7(4x + 3)
f(x) = 5(3²) - 7(4(3) + 3)
Follow PEMDAS. First, solve the parenthesis
3² = 9
4(3) + 3 = 12 + 3 = 15
f(x) = 5(9) - 7(15)
Multiply
f(x) = 45 - 105
Simplify. Subtract
f(x) = 45 - 105
f(x) = -60
f(x) = -60 is your answer
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