19.在一条40米长的路一边栽树(两端都栽),每4米栽一棵树,一共可以栽( )棵树.
| A. | 9 | B. | 10 | C. | 11 |
17.解方程.
0 136279 136287 136293 136297 136303 136305 136309 136315 136317 136323 136329 136333 136335 136339 136345 136347 136353 136357 136359 136363 136365 136369 136371 136373 136374 136375 136377 136378 136379 136381 136383 136387 136389 136393 136395 136399 136405 136407 136413 136417 136419 136423 136429 136435 136437 136443 136447 136449 136455 136459 136465 136473 199269
| 1.2x-0.9x=8.7 | 9x-1.8=2.7 | 6x+x=42 |
| 1.2x-x=0.96 | 5y-3.7=8.5 | 7a+3×4=40. |