Question

Dada as função f(x) = 5x + 2 e g(x ) = 2x 2 + x - 1 , o valor de f ( g(0 ) ) é :

Answer 1

Resposta:

Encontremos a expressão da função composta $f \left( g(x) \right)$ :

$f \left( g(x) \right) = 5 \cdot g(x) + 2\\\\\Longleftrightarrow f \left( g(x) \right) = 5\cdot (2x^2 + x - 1) + 2\\\\\Longleftrightarrow f \left( g(x) \right) = 10x^2 + 5x -5 + 2\\\\\Longleftrightarrow f \left( g(x) \right) = 10x^2 + 5x -3.$

Calculemos, agora, o valor de $f \left( g(0) \right):$

$f \left (g(0) \right) = 10 \cdot 0^2 + 5 \cdot 0 - 3 \\\\\Longleftrightarrow \boxed{f \left (g(0) \right) = -3.}$