In Multiplication of Monomial by Binomial,monomial means single number and Binomial has two terms.
For solving this multiplication use the following steps:
1) Monomial is outside the parenthesis (bracket).
2) Binomial is inside the parenthesis.
3) Use a distributive property to open the parenthesis.
4) Distributive property ---> Multiply each term of the parenthesis by the monomial keeping the addition or subtraction sign same.
1) Multiply : 3x(x + 4)
As 3x is outside the parenthesis, multiply x and 4 by 3x
3x(x + 4) = 3x . x + 3x . 4
= 3x1 + 1 + 12x
= 3x2 + 12x