(2x-3y)/4+2(x+2y)/5=1 3(2x-3y)/4-(x+2y)/5=﹣4 加减消元法
x+y/2+x-y/3=6,4(x+y)-5(x-y)=2用加减消元法解方程组
用加减消元法(1)2x-y=8 2x+5y=-4 (2)2x+5y=17 2x-3y=1 (3)x-y=5 2x+3y-
5x-3y=2,4y+2x=6用加减消元法
4(x+2y)=12,3x=5+2y(加减消元法)
方程组3x+2y=5 5x+4y=7 j加减消元法
解方程组{2x-y=5 4x+3y=15 加减消元法.
解方程组{3x+2y=8 5x-4y=6 加减消元法.
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
{2X-3Y=5{2Y-5X+4=0加减消元!
用加减消元法解方程组{4x-5y=5,2x+3y=-25
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(