Answer:
2
Step-by-step explanation:
a1 = -128/27
a2 = 32/9
a3 = -8/3
Therefore, a = a1 = -128/27
r = a3 ÷ a2 = -8/3 ÷ 32/9 = -3/4
So [tex]a_n=ar^{n-1}=-\frac{128}{27} (-\frac{3}{4})^{n-1}[/tex]
Therefore, a4 = (-128/27) x (-3/4)^(4-1)
= (-128/27) x (-3/4)^3
= (-128/27) x (-27/64)
= 2
