Question

Find the 21st term of the arithmetic sequence: 18,23,28,33,...

Answer 1

`18,23,28,33,... \\ a_1=18 \\ d=5 \\ \\ a_n=a_1+d(n-1) \\ a_(21)=a_1+20d \\ a_(21)=18+20 * 5 \\ a_(21)=18+100 \\ \boxed{a_(21)=118}`