Because the formula under the root sign must not be less than 0, both 4-x 2 and x 2-4 should be greater than or equal to 0, so x is equal to 2 or -2.

And because the denominator cannot be equal to 0, so x+2 is not equal to 0, so X = 2；;

So y=20 12.

So x2+y-3 = 4+2012-3 = 2013.

Hope to adopt, thank you.