Answer:
a₁ = 3
Step-by-step explanation:
The sum to n terms of a geometric sequence is
[tex]S_{n}[/tex] = [tex]\frac{a_{1}(r^{n}-1) }{r-1}[/tex]
where a₁ is the first term and r the common ratio
Here [tex]S_{6}[/tex] = 189 and r = 2, thus
[tex]\frac{a_{1}(2^{6}-1) }{2-1}[/tex] = 189, that is
a₁( 64 - 1) = 189
63a₁ = 189 ( divide both sides by 63 )
a₁ = 3
