解方程组 1）6y-7x=40 5x-2y=-8 2) 3x+4y=20 4x+3y=15

解方程组：2(x-y)/3-x+y/4=-1 ,6(x+y)-4(2x-y)=16 解方程组 x-y/3-x+y/4=2 x-y/6-x+y/8=3 解方程组 10（x-y)=3(x+y)+15 6(x+y)=4(2x-y)+16 解方程组 {(x+y)/2+(x-y)/3=6 5(x+y)-2(x-y)=4 解方程组 X+Y/2+X-Y/3=6 4[X+Y]-5[X-Y]=2 解二元一次方程组{3(x+y)-4(x-y)=4,x+y/2+x-y/6=1 解方程组3(x+y)-4(x-y)=4和(x+y)/2+(x-y)/6=1 解方程组：x+y/2+x-y/3=6 4(x+y)-5(x-y)=12 解二元一次方程组{3(x+y)-(x-y)=4,x+y/2+x-y/6=1 解二元一次方程组：3(x+y)-4(x-y)=4,x+y/2+x-y/6+1 y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组, 解方程组：（0.2x+0.1y）/2- （4x-y）/10=（x-y）/5+ (3x+0.5y)/30 (3x+2y-1