Practicing Success
If $x^4 + x^2y^2 + y^4 = 133$ and $x^2 - xy + y^2 = 7$, then what is the value of xy? |
8 12 4 6 |
6 |
If $x^4 + x^2y^2 + y^4 = 133$ $x^2 - xy + y^2 = 7$--- (1) what is the value of xy? x4 + x2y2 + y4 = (x2 – xy + y2) (x2 + xy + y2) Then , $x^2 + xy + y^2 = \frac{133}{7}$ = 19----- (2) From equation 1 and 2 we get, xy = 6 |