Question

numa p.a, a8=52 e a10= 56.calcule a razão

Answer 1

an = ak + ( n - k ).r
52 = 56 + ( 8 - 10 ) . r
52 = 56 - 2.r
52 - 56 = -2. r
-4 / -2 = r
r = 2

Razão  =  2