4.
如图,四边形ABCD中,点M,N分别在AB,BC上,将△BMN沿MN翻折,得△FMN,若MF∥AD,FN∥DC,则∠B的度数是( )
| A. | 80° | B. | 100° | C. | 90° | D. | 95° |
2.方程2x+3y=8的正整数解的个数是( )
| A. | 4 | B. | 3 | C. | 2 | D. | 1 |
1.若m<n,则下列各式正确的是( )
| A. | $\frac{m}{2}$>$\frac{n}{2}$ | B. | m-2<n-2 | C. | -3m<-3n | D. | -a2m<-a2n |
18.
如图,在△ABC中,∠ACB=90°,D是AB上一点,连接CD,∠ACD=∠B,若BC=13cm,CD=5cm,则BD=( )
| A. | 8cm | B. | 9cm | C. | 10cm | D. | 12cm |
17.若x>y,则下列等式不一定成立的是( )
| A. | x+4>y+4 | B. | -3x<-3y | C. | $\frac{x}{3}>\frac{y}{3}$ | D. | x2>y2 |
16.下列各数中,与8${\;}^{\frac{1}{2}}$-2${\;}^{\frac{1}{2}}$相等的是( )
0 284752 284760 284766 284770 284776 284778 284782 284788 284790 284796 284802 284806 284808 284812 284818 284820 284826 284830 284832 284836 284838 284842 284844 284846 284847 284848 284850 284851 284852 284854 284856 284860 284862 284866 284868 284872 284878 284880 284886 284890 284892 284896 284902 284908 284910 284916 284920 284922 284928 284932 284938 284946 366461
| A. | 2${\;}^{\frac{1}{2}}$ | B. | 6${\;}^{\frac{1}{2}}$ | C. | 4${\;}^{\frac{1}{2}}$ | D. | 3 |