13.已知x-2y=3,那么代数式3-2x+4y的值是( )
| A. | -3 | B. | 0 | C. | 6 | D. | 9 |
12.
如图,在⊙O中,$\widehat{AB}$=$\widehat{AC}$,∠AOB=40°,则∠ADC的度数是( )
| A. | 40° | B. | 30° | C. | 20° | D. | 15° |
10.
如图,直线a∥b,点B在直线b上,且AB⊥BC,∠1=55°,那么∠2的度数是( )
| A. | 20° | B. | 30° | C. | 35° | D. | 50° |
9.下列计算正确的是( )
0 283656 283664 283670 283674 283680 283682 283686 283692 283694 283700 283706 283710 283712 283716 283722 283724 283730 283734 283736 283740 283742 283746 283748 283750 283751 283752 283754 283755 283756 283758 283760 283764 283766 283770 283772 283776 283782 283784 283790 283794 283796 283800 283806 283812 283814 283820 283824 283826 283832 283836 283842 283850 366461
| A. | x2•x3=x5 | B. | x6+x6=x12 | C. | (x2)3=x5 | D. | x-1=x |