Question

A razão da P.G. (a, a+3, 5a-3, 8a) é:

Answer 1

(a+3)/a = (5a-3)/(a+3)
a (5a-3) = (a+3)^2
5a^2-3a=a^2+6a+9
4a^2-9a-9=0
a=(9 +/-raiz (9^2-4×4×-9))/2×4
a=(9+/-raiz (225))/8
a=(9+/-15)/8
a=3

PG ( 3, 6, 12, 24)
razão = 6/3=2