10.两整式相乘的结果为a2-a-12 的是( )
| A. | (a+3)(a-4) | B. | (a-3)(a+4) | C. | (a+6)(a-2) | D. | (a-6)(a+2) |
9.下列计算正确的是( )
| A. | 2x3•3x4=5x7 | B. | 4a3•2a2=8a5 | C. | 2a3+3a3=5a6 | D. | 12x3÷4x3=3x3 |
8.若1<x<2,则$\sqrt{4-4x+{x}^{2}}$+$\sqrt{{x}^{2}+2x+1}$化简的结果是( )
0 284948 284956 284962 284966 284972 284974 284978 284984 284986 284992 284998 285002 285004 285008 285014 285016 285022 285026 285028 285032 285034 285038 285040 285042 285043 285044 285046 285047 285048 285050 285052 285056 285058 285062 285064 285068 285074 285076 285082 285086 285088 285092 285098 285104 285106 285112 285116 285118 285124 285128 285134 285142 366461
| A. | 2x-1 | B. | -2x+1 | C. | -3 | D. | 3 |