12.下列等式中,正确的是( )
| A. | 3a-2a=1 | B. | (a2)3=a5 | C. | (-2a3)2=4a6 | D. | (a-b)2=a2-b2 |
11.有大小两种圆珠笔,3枝大圆珠笔和2枝小圆珠笔的售价是14元,2枝大圆珠笔和3枝小圆珠笔的售价为11元.设大圆珠笔为x元/枝,小圆珠笔为y元/枝,根据题意,列方程组正确的是( )
0 284732 284740 284746 284750 284756 284758 284762 284768 284770 284776 284782 284786 284788 284792 284798 284800 284806 284810 284812 284816 284818 284822 284824 284826 284827 284828 284830 284831 284832 284834 284836 284840 284842 284846 284848 284852 284858 284860 284866 284870 284872 284876 284882 284888 284890 284896 284900 284902 284908 284912 284918 284926 366461
| A. | $\left\{\begin{array}{l}{3x-2y=11}\\{2x+3y=14}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{3x+2y=14}\\{2x+3y=11}\end{array}\right.$ | ||
| C. | $\left\{\begin{array}{l}{14x-11y=3}\\{2x+3y=11}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{3x-2y=11}\\{2x+3y=14}\end{array}\right.$ |