Question

Se fog(x)= 5x + 8 e f(x)= 2x + 2 qual o valor de g(-1) ?

Answer 1

fog(x) = 5x + 8 é o mesmo que;

f(g(x)) = 5x + 8
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f(x) = 2x + 2

f(g(x)) = 2g(x) + 2

5x + 8 = 2g(x) + 2

5x + 8 - 2 = 2g(x)

5x + 6 = 2g(x)

g(x) = (5x + 6)/2
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g(-1) = (5(-1) + 6)/2

g(-1) = (-5 + 6)/2

g(-1) = 1/2