Question

Calculando o vértice da funcao f(x)=x-4x-5

Answer 1

Use as fórmulas:

$\Delta=b^2-4.a.c\\ \\x_V=\frac{-b}{2a}\\ \\y_V=\frac{-\Delta}{4a}\\ \\ \Delta=(-4)^2-4.1.(-5)=16+20=36\\ \\ x_V=\frac{-(-4)}{2.1}=\frac{4}{2}=2\\ \\ y_V=\frac{-36}{4.1}=-9\\ \\ \boxed{V(2,-9)}$