12.若点P1(x1,x2),P(x2,y2)在反比例函数y=$\frac{k}{x}$(k>0)的图象上,且x1<x2,则( )
| A. | y1<y2 | B. | y1>y2 | C. | y1=y2 | D. | 以上都不对 |
11.下列各运算中,计算正确的是( )
| A. | x2+x2=x4 | B. | $\sqrt{9}$=3 | C. | a0=1 | D. | (-3ab2)2=6a2b4 |
7.下列计算中,正确的是( )
0 283108 283116 283122 283126 283132 283134 283138 283144 283146 283152 283158 283162 283164 283168 283174 283176 283182 283186 283188 283192 283194 283198 283200 283202 283203 283204 283206 283207 283208 283210 283212 283216 283218 283222 283224 283228 283234 283236 283242 283246 283248 283252 283258 283264 283266 283272 283276 283278 283284 283288 283294 283302 366461
| A. | -a(3a2-1)=-3a3-a | B. | (-2a-3)(2a-3)=9-4a2 | ||
| C. | (2+x)(x-2)=4-x2 | D. | (ab-c)(-c+ab)=a2b2-c2 |