SOLUTION: Can someone please help me solve this system by substitution? {{{ x^2+4y^2=20}}} {{{ xy=4 }}}

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Question 989407: Can someone please help me solve this system by substitution?
+x%5E2%2B4y%5E2=20
+xy=4+
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Try y=4%2Fx and then make the first equation x%5E2%2B4%284%2Fx%29%5E2=20; if you can work through that, then you will just do the algebra steps; otherwise you might want help with this equation. You will have an equation in quadratic form.

Next step might be, ...
x%5E4%2B4%2A4%5E2=20x%5E2
x%5E4-20x%5E2%2B64=0--------quadratic form.