Question

Dada a função f(x)=
$-4 {x}^{2} - 8x + 10$
sendo P(a,b) vértice, calcule |a+b|

Answer 1

Como a corresponde ao eixo x, a = Xv, e b = Yv
$-4 {x}^{2} - 8x + 10\\\\ X_v= \frac{-b}{2a}\\\\ X_v= \frac{-(-8)}{2*-4}\\\\ X_v= \frac{8}{-8}\\\\ X_v=-1=a\\\\\\ Y_v= \frac{-\delta}{4a}\\\\ Y_v= \frac{-((-8)^2-4*-4*10)}{4*-4}\\\\ Y_v= \frac{-(64+160)}{-16}\\\\ Y_v= \frac{-224}{-16}\\\\ Y_v=14=b\\\\ |a+b|=|-1+14|\\ |a+b|=13$