It is intercepting eliminating, I just forgot to put its values. Let me post it again.

x^2+y=9, x^2-y=1

In order to know the value of y, I change the sign of below equation I.e minus into plus and plus into minus:

x^2+y=9
-x^2+y=-1
---------------
0+2y=8

Y=4

But in book, its answer is 5. Please solve it.

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