Question

The figure above shows the graph of a quadratic function in the xy-plane. Of all the points (x, y) on the graph, for what value of x is the value of y greatest?

Answer 1

$y$ is greatest at vertex of parabola

Vertical line through vertex divides the parabola into two equal parts ie, it is the axis of symmetry

$\therefore$it occurs at $x=\frac{3+7}{2}$

$\therefore x=5$