First, let's combine all like terms on the right side of the equation.
We get the formula
y=−5x2−6x+10
Now, it's important to note that the x coordinate of the vertex can be written in the form
−b2a for parabolas in the form of y=ax2+bx+c
Thus plugging in -5 and -6, we get
x=6/−10=−3/5=−0.6
Plugging this back into the equation, we fins that y=11.8
Thus the vertex is at (−0.6,11.8)
So our answer is (−0.6,11.8)
Thanks! :)