SOLUTION: If x + y = 4 and xy = -12; what is the value of x^2 + 5xy + y^2?

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Question 1132819: If x + y = 4 and xy = -12; what is the value of x^2 + 5xy + y^2?
Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13203)   (Show Source): You can put this solution on YOUR website!




Evaluate using the given values of (x+y) and (xy).
Answer by ikleyn(52834)   (Show Source): You can put this solution on YOUR website!
.

  x^2 + 5xy + y^2 = (x^2 + 2xy + y^2) + 3xy = (x+y)^2 + 3xy = 


        now substitute x+y = 4 and xy = -12 to get


=  = 16 - 36 = -20.       ANSWER

Solved.


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