8x-(-3y-5)=8x+3y+5这样变号对嘛?

5(x+y)²-3(x+y)³+(y+x)²-8(y+x)³ 怎么样求解这样的多项式? 8x-(-3y-5)=8x+3y+5这样变号对嘛? (2x+y)²+(x+3y)(x-3y)-x(5x+8y)因式分解 [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值 （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x (3x-4y)(5x-4y)-(7x-8y)(6y-5x) 5(x-y)^2-(x-y)-8(x-y)^2-3(x-y) 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 7y=x+3,8y=x+5 7y=x+3,8y-5=x 7y=x+3,8y+5=x x+y=8,5x+3y=34;