Question

solve it: given: l=a+(n-1) d . first make subject n and then find n if l=31 , a=15 and d=2 (with solution)

Answer 1

l=a+(n-1)d 31=15+(n-1)2 31-15=2n-2 16+2=2n 18=2n 18/2=n 9=n