3x+7y=23 4x-3y=6
(3x-4y)(5x-4y)-(7x-8y)(6y-5x)
化简 3(X-Y)²-4(X-Y)+7(X-Y)-6(X-Y)²
x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8
已知3X+4Y=23,3Y+4X=25,求X,Y
x-4y分之3x + 4y-x分之x+y - x*x-4y分之7y
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
2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
计算:(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1