Question

What is the vertex of y= -x^2+10x

Answer 1

$y = -x^2+10x\implies y = -x^2+10x+0 \\\\[-0.35em] ~\dotfill\\\\ \textit{vertex of a vertical parabola, using coefficients} \\\\ y=\stackrel{\stackrel{a}{\downarrow }}{-1}x^2\stackrel{\stackrel{b}{\downarrow }}{+10}x\stackrel{\stackrel{c}{\downarrow }}{+0} \qquad \qquad \left(-\cfrac{ b}{2 a}~~~~ ,~~~~ c-\cfrac{ b^2}{4 a}\right) \\\\\\ \left(-\cfrac{ 10}{2(-1)}~~~~ ,~~~~ 0-\cfrac{ (10)^2}{4(-1)}\right)\implies \left( \cfrac{10}{2}~~,~~\cfrac{100}{4} \right)\implies (5~~,~~25)$