Question

Encontre a raiz da seguinte função quadrática f(x)= -X²+8X

Answer 1

$x_{1,\:2}=\frac{-8\pm \sqrt{8^2-4\left(-1\right)\cdot \:0}}{2\left(-1\right)}\\x_{1,\:2}=\frac{-8\pm \:8}{2\left(-1\right)}\\x_1=\frac{-8+8}{2\left(-1\right)},\:x_2=\frac{-8-8}{2\left(-1\right)}\\x=0,\:x=8$