Alright:
Multiplication is short hand for addition. So when you have 6x, you are saying that you have
x + x + x + x + x + x
Exponents are shorthand for multiplication. So when you say x^2, you are saying that you have
x * x
So you have:
(x + x + x + x + x + x)(x * x)
You can change that (using associativity, hopefully you know what that is) to be:
(x * x * x) + (x * x * x) + (x * x * x) + (x * x * x) + (x * x * x) + (x * x * x)
Which, using our shorthand for multiplication (exponents) becomes
x^3 + x^3 + x^3 + x^3 + x^3 + x^3
Which, using our shorthand for addition (multiplication) becomes
6x^3
Hope that helps!