15.下列因式分解正确的有几个( )
①x3-x=x(x2-1)
②m2+m-6=(m+3)(m-2)
③x2+y2=(x+y)(x-y)
④(a+4)(a-4)=a2-16
⑤-x2+(-2)2=(x+2)(x-2)
①x3-x=x(x2-1)
②m2+m-6=(m+3)(m-2)
③x2+y2=(x+y)(x-y)
④(a+4)(a-4)=a2-16
⑤-x2+(-2)2=(x+2)(x-2)
| A. | 4个 | B. | 3个 | C. | 2个 | D. | 1个 |
14.下列合并同类项正确的是( )
| A. | -2xy-2xy=0 | B. | 3a2b-3ab2=0 | C. | 3m3+2m3=5m3 | D. | 3a2-a2=2 |
13.下列运算中结果正确的是( )
| A. | 3a+2b=5ab | B. | 5y-3y=2 | C. | 2x2y-3x2y=-x2y | D. | -3x+5x=-8x |
12.下列各对式子中,是同类项的是( )
| A. | a2b与3ab2 | B. | x与π | C. | -3xy2与-3ab2 | D. | $\frac{1}{6}$ab与4ba |
10.$\sqrt{81}$的平方根是多少( )
| A. | ±9 | B. | 9 | C. | ±3 | D. | 3 |
9.若关于x的方程x2-3x+a=0左边是完全平方式,则a的值为( )
| A. | 9 | B. | $\frac{9}{4}$ | C. | ±9 | D. | $±\frac{9}{4}$ |
8.观察下列等式:31=3,32=9,33=27,34=81,35=243,36=729,37=2187,…解答下列问题:3+32+33+34+…+32016的末位数字是( )
| A. | 0 | B. | 1 | C. | 3 | D. | 7 |
7.下列结果计算正确的是( )
| A. | (-1)-1=1 | B. | (-1)0=0 | C. | ${(-\frac{1}{2})^{-2}}=-4$ | D. | -(-1)2=-1 |
6.若代数式2x2-3x+1的值是5,则代数式4x2-6x-3的值为( )
0 292187 292195 292201 292205 292211 292213 292217 292223 292225 292231 292237 292241 292243 292247 292253 292255 292261 292265 292267 292271 292273 292277 292279 292281 292282 292283 292285 292286 292287 292289 292291 292295 292297 292301 292303 292307 292313 292315 292321 292325 292327 292331 292337 292343 292345 292351 292355 292357 292363 292367 292373 292381 366461
| A. | 10 | B. | 2 | C. | 1 | D. | 5 |