Please help!!!

x² + y   =   4

                            Square both sides of the equation.

(x² + y)²  =  4²

                                       Expand the left side.

(x² + y)(x² + y)  =  16

 

x⁴ + 2x²y + y²  =  16

                                       Rearrange the terms on the left side.

2x²y + x⁴ + y²  =  16

                                       Since  x⁴ + y² = 10  we can substitute  10  in for  x⁴ + y²

2x²y + 10  =  16

                            Subtract  10  from both sides.

2x²y  =  6

                            Divide both sides by  2

x²y  =  3