Question

numa PA a11=44,a1=4 e r =5 calcule n

Answer 1

an = a1 + ( n -1) . r
44 = 4 + (  n  -1) . 5
44 = 4 + 5n - 5
44 = -1 + 5n
45 = 5n  
n = 45 / 5
n = 9

PA com 9 termos