Question

Se f(x) = X² + 3x +5 , então quanto vale f (-1) ?

Answer 1

$\sf     f(x) = x {}^{2} + 3x + 5 \\ \\ \sf     f( - 1) = - 1 {}^{2} + 3 \cdot - 1 + 5 \\ \\ \sf     f ( - 1) = - 1 \cdot - 1 + 3 \cdot - 1 + 5 \\ \\ \sf     f ( - 1) = 1 + 3 \cdot - 1 + 5 \\ \\ \sf     f( - 1) = 1 - 3 + 5 \\ \\ \sf     f( - 1) = - 2 + 5 \\ \\ \sf     {\color{red}f( - 1) = 3}$

Att: Nerd1990