10.小明用17元买了1支笔和某种笔记本3个,已知笔记本的单价比笔的单价的2倍还多1元,设笔每支x元,笔记本每本y元,则所列方程组为( )
| A. | $\left\{\begin{array}{l}{x+3y=17}\\{x=2y+1}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x+3y=17}\\{y=2x+1}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{y+3x=17}\\{x=2y+1}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{y+3x=17}\\{y=2x+1}\end{array}\right.$ |
9.方程组$\left\{\begin{array}{l}{2x-y=3}\\{x+3y=5}\end{array}\right.$的解是( )
| A. | $\left\{\begin{array}{l}{x=-1}\\{y=2}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x=1}\\{y=-1}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x=1}\\{y=2}\end{array}\right.$ |
4.为了让山更绿、水更清,确保到2015年实现全省森林覆盖率达到63%的目标,已知2013年全省森林覆盖率为60.05%,设从2013年起全省森林覆盖率的年平均增长率为x,则可列方程( )
| A. | 60.05(1+2x)=63% | B. | 60.05(1+3x)=63 | C. | 60.05(1+x)2=63% | D. | 60.05%(1+x)2=63% |
3.已知关于x的方程$\frac{1}{4}$x2-(m-2)x+m2=0有两个相等的实数根,则方程的根为( )
0 305929 305937 305943 305947 305953 305955 305959 305965 305967 305973 305979 305983 305985 305989 305995 305997 306003 306007 306009 306013 306015 306019 306021 306023 306024 306025 306027 306028 306029 306031 306033 306037 306039 306043 306045 306049 306055 306057 306063 306067 306069 306073 306079 306085 306087 306093 306097 306099 306105 306109 306115 306123 366461
| A. | x1=x2=1 | B. | x1=x2=-2 | C. | x1=x2=-1 | D. | x1=x2=2 |