2.由方程组$\left\{\begin{array}{l}{2x+m=1}\\{y-4=m}\end{array}\right.$可得出x与y的关系是( )
| A. | 2x-y=5 | B. | 2x+y=5 | C. | 2x+y=-5 | D. | 2x-y=-5 |
1.已知$\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$和$\left\{\begin{array}{l}{x=3}\\{y=0}\end{array}\right.$是方程ax-by=3的解,则a、b的值为( )
| A. | a=-1,b=-1 | B. | a=-1,b=1 | C. | a=1,b=-1 | D. | a=1,b=1 |
20.若(m-1)x=6是关于x的一元一次方程,则m的取值为( )
0 285531 285539 285545 285549 285555 285557 285561 285567 285569 285575 285581 285585 285587 285591 285597 285599 285605 285609 285611 285615 285617 285621 285623 285625 285626 285627 285629 285630 285631 285633 285635 285639 285641 285645 285647 285651 285657 285659 285665 285669 285671 285675 285681 285687 285689 285695 285699 285701 285707 285711 285717 285725 366461
| A. | 任何数 | B. | 不等于1的数 | C. | 1 | D. | 不等于1的整数 |