Answer:
105
Step-by-step explanation:
f(x) = 8x² + x -9
g(x) =5x²
(f+g)(x) = 8x² + x - 9 + 5x²
Collect like terms
8x² +5x² + x - 9
13x² + x - 9
b) (f+g)(-3) = 13x² + x - 9 when x =-3
= 13×-3² + (-3) - 9
= (13×9) -3 -9
= 117 -3 -9
= 105
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