[填空题]
Two college students, David azcog:3e xl ,;xnd Lisa, d; yjo)ixw8s,z2s.g y6ugp:2wbae gr+ ecide to invest money they have saved from working part-time jobs. David's investment striga 6y)x:.gpe2s bgrs2 yujw + o;wz8,ategy results in an increase of his investment 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 .
