so we need to combine like terms
(-x^2 - 6x - 3) + (-4x - 7)
-6x and -4x are like terms, so are -7 and -3
so we add because it says to add the two equations
-6x + -4x = 10x
(two negatives make a positive)
-7 + -3 = 10
-x^2 does not have any like terms so it stays the same
now we have
-x^2 - 10x - 10
hope this helped!!