Question

If (x + y)^2 = 1 and xy = -4, what is the value of x^2 + y^2?

Answer 1

Answer:

$(x + y)^{2} = 1\\xy = -4\\x^{2} + y^{2} \\= x^{2} + 2xy + y^{2} - 2xy \\= (x^{2} + 2xy + y^{2}) - 2xy\\= (x+y)^{2} - 2xy\\= 1 - 2 *(-4) \\= 9$

Hope this helps!

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