Respuesta :

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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