Solve. Do not use decimals.
x^2+xy=3
3x^2+2xy-y^2=7
Are you solving for x in terms of y ?
then ...
x^2+xy-3 = 0
now treat it as a quadratic where a=1, b=y and c=-3
x = (-y ± √(y^2 - 4(1)(-3))/2
= (-y ± √(y^2 + 12))/2
try the second in a similar way.