14.已知单项式4x3ym与-3xn-1y3的和是单项式,则这两个单项式的和是( )
| A. | x2y3 | B. | x3y2 | C. | xn-1ym | D. | xn+2ym+2 |
13.在平面直角坐标系中,点A到x轴的距离为1,到y轴的距离为2.若点A在第二象限,则A点坐标为( )
0 282704 282712 282718 282722 282728 282730 282734 282740 282742 282748 282754 282758 282760 282764 282770 282772 282778 282782 282784 282788 282790 282794 282796 282798 282799 282800 282802 282803 282804 282806 282808 282812 282814 282818 282820 282824 282830 282832 282838 282842 282844 282848 282854 282860 282862 282868 282872 282874 282880 282884 282890 282898 366461
| A. | (-1,2) | B. | (2,-1) | C. | (-2,1) | D. | (2,1) |