4.
y=-2x² + 8x + 5
So, the function is a quadratic function in the form:
y=ax² + bx + c
So:
a=-2
b=8
c=5
To answer the next points we have to graph it:
As we can see, the graph opens down (a<0)
Since it opens down it has a maximum
The axis of symmetry is the vertical line that separates the function into 2 equal halves, in this case, the vertical line is x=2
The vertex is the maximum point (2,13)
and the y-intercepts are where x values are 0 (-0.55,0) and (4.55,0)