Algebra

First, let's combine all like terms and see what we get. We find that

$y=-5x^{2}-6x+10$

Now, the x value of the vertex can be written in the equation $-b/2a$ for quadratics in the form $ax^2+bx+c$

Thus, we have

$x=-(-6)/2(-5) = -3/5$

Plugging this in to find the y value, we get

$y=11.8$

Thus, the vertex is at $(-0.6, 11.8)$

So our answer is $(-0.6, 11.8)$

Thanks! :)