5.点M(2,1)关于x轴对称的点的坐标是( )
| A. | (1,-2) | B. | (-2,1) | C. | (2,-1) | D. | (-1,2) |
4.
如图,笑脸盖住的点的坐标可能为( )
| A. | (5,2) | B. | (3,-4) | C. | (-4,-6) | D. | (-1,3) |
3.下列长度的线段不能构成直角三角形的是( )
0 279348 279356 279362 279366 279372 279374 279378 279384 279386 279392 279398 279402 279404 279408 279414 279416 279422 279426 279428 279432 279434 279438 279440 279442 279443 279444 279446 279447 279448 279450 279452 279456 279458 279462 279464 279468 279474 279476 279482 279486 279488 279492 279498 279504 279506 279512 279516 279518 279524 279528 279534 279542 366461
| A. | 8,15,17 | B. | 1.5,2,3 | C. | 6,8,10 | D. | 5,12,13 |