8.设a是绝对值最小的有理数,b是最大的负整数,c是倒数等于自身的有理数,则a-b+c的值为( )
| A. | 2 | B. | 0 | C. | 0或2 | D. | 0或-2 |
5.下列各式中,运算结果正确的是( )
| A. | (x+7)(x-8)=x2+x-56 | B. | (x+2)2=x2+4 | ||
| C. | (7-2x)(8+x)=56-2x3 | D. | (3x+4y)(3x-4y)=9x2-16y2 |
4.若|a+b-1|+(a-b+3)2=0,则ab=( )
| A. | 1 | B. | 2 | C. | 3 | D. | -1 |
1.如果x2=144,那么x的值是( )
| A. | 12 | B. | -12 | C. | ±12 | D. | ±$\sqrt{12}$ |
20.下列等式由左边到右边的变形中,属于因式分解的是( )
| A. | (a+1)(a-1)=a2-1 | B. | -18x4y3=-6x2y2•3x2y | ||
| C. | x2+2x+1=x(x+2)+1 | D. | a2-6a+9=(a-3)2 |
19.下列等式成立的是( )
0 285976 285984 285990 285994 286000 286002 286006 286012 286014 286020 286026 286030 286032 286036 286042 286044 286050 286054 286056 286060 286062 286066 286068 286070 286071 286072 286074 286075 286076 286078 286080 286084 286086 286090 286092 286096 286102 286104 286110 286114 286116 286120 286126 286132 286134 286140 286144 286146 286152 286156 286162 286170 366461
| A. | $\sqrt{{a}^{2}}$=a | B. | a2+4a+2=(a+2)2 | C. | a2÷(a2+a)=$\frac{1}{a}$+1 | D. | $\frac{ab}{ab-{b}^{2}}$=$\frac{a}{a-b}$ |