(3x+y)^2+(x-y)(y-x)=9x²+6xy+y²+y²-x²=8x²+6xy+2y²
2
1)(x+y)/y+y(x-y)=(x²-y²+y²)/y(x-y)=x²/y(x-y)
2)x/(x-y)*y(x-y)/x²=y/x
3
3y/2-2y=3 3/4
-y/2=3 3/4
y=-3 3/4:1/2=-15/4*2
y=-15/2
y=-7,5