Question

O valor máximo da função F: R--R definida por F(x)=-x²+6x+7 é:
A)7
B)6
C)3
D)16

Answer 1

Hola,

$a=-2\\b=6\\c=7 \\\Delta=b^2-4ac\\ \Delta=-\frac{\Delta}{4a}\\ v_y= -\frac{\Delta}{4a}\\ \Delta=6^2-4*(-1)*7\\\Delta=36+28\\ \Delta=64\\v_y= -\frac{\Delta}{4a}\\ v_y =-\frac{64}{4*(-1)}\\ v_y = \frac{64}{4}\\\boxed{v_y = 16},letra~d$