To multiply (2-x)^3, we have several ways to do it. One solution is by Binomial Theorem and another is by simply multiplying the expression (2-x) by itself and the result by itself again.
Solution by Binomial Theorem
(a-b)^3=a^3-3a^2b+3ab^2-b^3
So that
(2-x)^3=2^3-3(2)^2*x+3(2)(x^2)-x^3
(2-x)^3=8-12x+6x^2-x^3
Solution by multiplication
(2-x)^3=(2-x)(2-x)(2-x)
(2-x)^3=[2(2-x)-x(2-x)]*(2-x)
(2-x)^3=[4-2x-2x+x^2]*(2-x)
(2-x)^3=[4-4x+x^2]*(2-x)
(2-x)^3=[4*(2-x)-4x*(2-x)+x^2*(2-x)]
(2-x)^3=[8-4x-8x+4x^2+2x^2-x^3]
(2-x)^3=8-12x+6x^2-x^3
God bless....I hope the explanation is useful.