19.多项式x2-4x-12可以因式分解成( )
| A. | x(x-4)-12 | B. | (x-2)(x+6) | C. | (x+2)(x-6) | D. | (x+3)(x-4) |
15.
如图,正六边形ABCDEF的边CD与等腰三角形GCD的直角边CD重合,∠GCD=90°,点G在正六边形的内部,则∠EDG的度数为( )
0 284191 284199 284205 284209 284215 284217 284221 284227 284229 284235 284241 284245 284247 284251 284257 284259 284265 284269 284271 284275 284277 284281 284283 284285 284286 284287 284289 284290 284291 284293 284295 284299 284301 284305 284307 284311 284317 284319 284325 284329 284331 284335 284341 284347 284349 284355 284359 284361 284367 284371 284377 284385 366461
| A. | 90° | B. | 85° | C. | 65° | D. | 75° |