Answer:
We know that the distributive property says this:
a(b+c) = ab + ac
If we apply this to our case, we can put
3a(2b+c) = 3a * 2b + 3a * c
When we multiply numbers and letters, we should multiply both of them:
3a * 2b + 3a * c = 3*2*a*b + 3*a*c = 6ab +3ac
We can use this when we find a number multiplied by a parenthesis..