若5x-4y=6,4x-5y=8,则x+y=( ),x-y=( )

若5x-4y=6,4x-5y=8,则x+y=( ),x-y=( ) 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若5x+3y=3x+4y=x+2y+6,则x+y=___ 已知|5x-y-8|+(7y-x+2)=0则4x+6y 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 x+y／y=5／4,则x／y=---------------- 若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? {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 5x-4y(y-x)=? 填空题 x+y/4=x-y/6=3x+12y+5/8 x= y= 3(2X+Y)+(2(2x-Y)=6 (8X+4y)-(10X-5Y)=2 y=|-x.x+4x+5| 若x/y=4/3 则3x+2y/2x-5y= 8x+6y-4x+5y x= y= 若4x-5y=0,则x+y分之x-y的值是 x+5y+2=0,则4^2x+y*8^y-x 若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( )若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( ）