SOLUTION: if x+y=-1 and xy=-12, find the value of x^2+y^2

Question 1077838: if x+y=-1 and xy=-12, find the value of x^2+y^2
Answer by ikleyn(52795) (Show Source): You can put this solution on YOUR website!
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 =  =  = (-1)^2 - 2*(-12) = 1 + 24 = 25.

Solved.

The key is to present as a combination of (x+y) (and possibly its degrees) and xy.

Then to replace in this expression (x+y) by the given number, as well as to replace xy by the other given number.

This way ALWAYS works, in any case you can meet in your practice.

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