If the sixth term of a sequence is 128 and the common ratio is 2, then what is the first term?

1

2

4

Geometric progresión:

we can calculate any term, using this rule:

an=a₁*r^ (n-1)

a₁=the first term

r=the common ratio

a₆=128

r=2

an=a₁ * r^ (n-1)

128=a₁ * 2⁶⁻¹

128=a₁ * 2⁵

128=a₁ * 32

a₁=128/32=4

Solution: a₁=4