SOLUTION: Please help me figure this out. If x-y=9 and xy=3, then x^2+y^2=? Answers: a) 36 b) 2(sqrt of 21) c) sqrt of 87 d) 84 e) 87

Question 121551: Please help me figure this out.
If x-y=9 and xy=3, then x^2+y^2=?
Answers:
a) 36
b) 2(sqrt of 21)
c) sqrt of 87
d) 84
e) 87
Answer by MathLover1(20850) (Show Source): You can put this solution on YOUR website!
If
and solve this system to find and

�..=>.�..=>.substitute into:
��.=>�.
...both sides multiply by

.....use quadratic formula to solve for

=>. �

=>. �..=>.

then
...

so, your answer is:
e) 87

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