pls help out with this example as well.

Find the term containing x^3 in the binomial expansion of
(3x − 3)^10

the expansion of (a+b)^10 starts out with a^10, so the term with a^3 is C(10,7)a^3b^7

So, since you have a = 3x and b = -3, that would be

C(10,7)(3x)^3(-3)^7
= 360(27x^3)(-2187)
= -7085880x^3