(5x+7y-3)×(5x-7y+3)=()
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
7x+[-3x-3(x-2y)]-[5x-(2x-y)]
(1)﹛2x-y=5 (2) 4x-y=1 (3)5x+y=2 7x-3y=20 y=2x+3 x-3y=4 (4)3x
若3x=7y,则y分之x= ,x:(x:y)=
若3x=7y,则y比x= ,x:(x+y)=
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
5(x-y)³-3(x-y)²+7(x-y)-5(x-y)³+(x-y)²-5(
(1){x+2y=0,3x+4y=6(2){5x+6y=16,7x-9y=5(3){9x-11y+1=0,4x-5y-3
(x-4y)分之(3x)+(4y-x)分之(x+y)-(x-4y)分之(7y)
2(x-y)+3(x+y)2-5(x-y)-8(x+y)2-(x-y)
2元一次方程组的答案(1)2x+3y=40 (2)5x+2y=18 (3)7x+2y=11 y=2x y=-x x-y=
若|3x-y-7|+(5x+2y-8)2=0,则x-y=______.