(1)3x-2y-(9x-7y)+2(4x-5y)
(1){x+2y=0,3x+4y=6(2){5x+6y=16,7x-9y=5(3){9x-11y+1=0,4x-5y-3
1.((y+2x)(-2x+y)+4(x+2y)^2)/3y 2.(2(x-y)^3-8(x-y)^2(x+y)+6y(
(3x-y)²-2x(4x-5y)-(x+2y)²
先化简再求值:(x-2y)²-(x+2y)(x-2y)-(x-3y)(x-y).其中x²+9y
去括号并合并同类项(1)3x-2(x+7)+2(2x+5) (2)(4x-3y)-[-(3y-x)+(x-y)]-5x
2(x-y)+3(x+y)2-5(x-y)-8(x+y)2-(x-y)
(X-3Y)(X+3Y)-(X+2Y)(X-4Y)-(2X-Y)2的平方
(1)﹛2x-y=5 (2) 4x-y=1 (3)5x+y=2 7x-3y=20 y=2x+3 x-3y=4 (4)3x
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
化简求值(x+5y)(x+4y)-(x-y)(x+y),其中x=一又2/5,y=-1/7
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
7x+[-3x-3(x-2y)]-[5x-(2x-y)]