1.若am=4,an=3,则am+n的值为( )
| A. | 21 | B. | 7 | C. | 1 | D. | 12 |
19.若$\sqrt{x+3}$+|y-2|=0,则$\sqrt{x^y}$=( )
| A. | -3 | B. | 3 | C. | ±3 | D. | $2\sqrt{2}$ |
18.在实数范围内,$\sqrt{x+1}$有意义,则x的取值范围是( )
0 284947 284955 284961 284965 284971 284973 284977 284983 284985 284991 284997 285001 285003 285007 285013 285015 285021 285025 285027 285031 285033 285037 285039 285041 285042 285043 285045 285046 285047 285049 285051 285055 285057 285061 285063 285067 285073 285075 285081 285085 285087 285091 285097 285103 285105 285111 285115 285117 285123 285127 285133 285141 366461
| A. | x≥1 | B. | x≥-1 | C. | x≤1 | D. | x≤-1 |