14.若(m+2)x${\;}^{{m}^{2}-3}$-2m=1,是关于x的一元一次方程,则m=( )
| A. | ±2 | B. | 2 | C. | -2 | D. | 1 |
9.下面方程组中,解为$\left\{\begin{array}{l}{x=1}\\{y=2}\end{array}\right.$的是( )
0 284582 284590 284596 284600 284606 284608 284612 284618 284620 284626 284632 284636 284638 284642 284648 284650 284656 284660 284662 284666 284668 284672 284674 284676 284677 284678 284680 284681 284682 284684 284686 284690 284692 284696 284698 284702 284708 284710 284716 284720 284722 284726 284732 284738 284740 284746 284750 284752 284758 284762 284768 284776 366461
| A. | $\left\{\begin{array}{l}{x-y=3}\\{3x-y=1}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x-y=-1}\\{3x+y=-5}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{x-2y=3}\\{3x+5y=-5}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x-y=-1}\\{3x+y=5}\end{array}\right.$ |