3(4x+6y)(4x-6y)-(-3x+4y(-4y-3x)

{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 (3x-4y)(5x-4y)-(7x-8y)(6y-5x) x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 化简 3(X-Y)²-4(X-Y)+7(X-Y)-6(X-Y)² ｛4/(x+y)+6/(x-y)=3 ｛9/(x-y)-1/(x+y)=1 1.（（y+2x)(-2x+y)+4(x+2y)^2)/3y 2.（2(x-y)^3-8(x-y）^2(x+y)+6y( x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8 [(x+y)^3]^6-3[(x+y)^3]^6X(x+y)^4X(-x-y)^2 (x-y)^3-(x-y)^4 因式分解 (x+3y-4)(2x-y)