What is the coefficient of x⁴ in the expansion of ( 1 + x)(1-x)^n

=(-1)^n (1-n)

Step-by-step explanation:

=coefficient of x^n in (1-x)^n + coefficient of x^n-1 in (1-x)^n

=(-1)^n ^nCn + (-1)^n-1 ^nCn -1

=(-1)^n (1-n)

for any of you who need the translation here it is

step-by-step explanation:

find the angular size of the equatorial radius of the earth, if the horizontal parallax of the sun

the answer is a.

step-by-step explanation:

in three games of golf, alex shot two under par four times.