Question

What is the Fourth term of (x-2)⁵

use the formula

`(n!)/(r!(n - r)!) \: a ^(n - r) b ^(r)`
to figure out the fourth term
show all work
​Find the indicated term using the binomial theorem.

Answer 1

-80 * x^2

Explanation:

(a + b)^n

(x + (-2))^5

a = x ; b = -2 ; n = 5 ; r = 3

n! / (r! * (n - r)!) * a^(n - r) * b^r

5! / (3! * (5 - 3)!) * x^(5 - 3) * (-2)^3

5! / (3! * 2!) * x^2 * (-8)

120 / (6 * 2) * x^2 * (-8)

-80 * x^2