m²+n²-n+4m+17/4=0
(m+2)²+(n-1/2)²=0
m=-2,n=1/2
(1)=4x²-12xy+9y²-9x²+y²=-5x²-12xy+10y²
(2)=(x²-y²)(x²+y²)=x^4-y^4
(3)=m²+n²+9-2mn-6m+6n
m²+n²-n+4m+17/4=0
(m+2)²+(n-1/2)²=0
m=-2,n=1/2
(1)=4x²-12xy+9y²-9x²+y²=-5x²-12xy+10y²
(2)=(x²-y²)(x²+y²)=x^4-y^4
(3)=m²+n²+9-2mn-6m+6n