Question

The graph of which quadratic equation is shown below?

Answer 1

y = −x2 + 6x + 8

y = −x2 − 6x + 8

y = x2 + 6x + 8

y = x2 − 6x + 8

Answer 2

Since it opens up, as x gets large f(x) gets very large. That means the coefficient of x^2 must be positive. Second point is that the vertex is (-3,-1). That is a solution of eqn. 3