find the fourth term of the geometric sequence whose first term is 8 and whose common ratio is -2, a under 4 = .

term(4) = ar^3

= 8(-2)^3
= 8(-8) = -64

To find the fourth term (a₄) of a geometric sequence, we can use the formula:

aₙ = a₁ * r^(n-1)

where:
aₙ is the nth term of the sequence
a₁ is the first term
r is the common ratio
n is the term number

In this case, the first term (a₁) is 8, the common ratio (r) is -2, and we want to find the fourth term (a₄).

Using the formula, we can plug in the given values:

a₄ = 8 * (-2)^(4-1)

Now, let's simplify this expression:

a₄ = 8 * (-2)^3
a₄ = 8 * (-8)
a₄ = -64

Therefore, the fourth term (a₄) of the geometric sequence is -64.