Question 751128
You are correct. Notice how adding -7x^2 + y to 7x^2 - y gives you 0


(-7x^2 + y) + (7x^2 - y)


-7x^2 + y + 7x^2 - y


(-7x^2 + 7x^2) + (y - y)


0x^2 + 0y


0 + 0


0


So that proves 7x^2-y is the additive inverse of -7x^2+y