Question

Multiply the following binomials by monomials

$(a-b)\times 4a$

Answer 1

Finding the multiplication

Multiplying by the horizontal method

$$\begin{gathered} (a-b)\times 4a=\left(a\right)\times \left(4a\right)-\left(b\right)\times \left(4a\right) \\ =\left(1\times 4\right)\left(a\times a\right)-\left(1\times 4\right)\left(b\times a\right) \\ =4a^2-4ab \end{gathered}$$

Hence, the product of algebraic expression is $4a^2-4ab$.