7.5x+7y=52 5x+2y=22 8.5x+5y=65 7x+7y=203 9.
7.5x+7y=52 5x+2y=22 8.5x+5y=65 7x+7y=203 9.
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
{5x-2y=7y+2x 3x+2y=22
20道二元一次方程组6.x+2y=21 3x+5y=56 7.5x+7y=52 5x+2y=22 8.5x+5y=65
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
5x+2y=83x-y=7
x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
{2x+y/3-2y=0 2(2x+y)-5=7y
7x-3y/5=5x-y/3-x+y/2 x-1/5=y+1/3
方程2分之x+y+2分之x-y=7,4(x+y)-5(x-y)=2
{ x-y/7-x+y/10=1/2 {2(x-y)+5(x+y)=3