[填空题]
Two college students x1dcc0dci )6h6ucl7ag-0mty 8i1z uj, David and Lisa, decide to invest money they have saved from working part-time jobs. David's investment strategy results in an increase of his investment8zy-u 1jm igt0 amount by 1000 each year. Lisa's investment strategy results in her investment amount increasing by 5% each year.
At the start of the second year of investing, David's total investment amount is 21000 and Lisa's is 11655.
1.Calculate
1.1.the original amount David invested.
$u_1$= .
1.2.the original amount Lisa invested.
$v_1$= .
During a certain year, n, Lisa's investment amount becomes larger than David's amount for the first time.
2.Find the value of n.
Lisa's amount will become larger than David's during year .
