3a*3b =3*3*a*b (commutative law of multiplication) =(3*3)*(a*b) (multiplicative associative law) =9ab

To multiply a monomial by a monomial, multiply their coefficients and powers of the same letters respectively. For letters contained in only one monomial, use its exponent as a factor of the product.

a*(b c d) =ab ac ad

To multiply a monomial by a polynomial, multiply each term of the polynomial by the monomial and then add the resulting products.

(a b)*(c d) =a(c d) b(c d) =ac ad bc bd

To multiply polynomials, multiply each term of one polynomial by each term of the other polynomial, and then add the resulting products.

Write a polynomial as the product of several integers

If there are the same factors, extract the common factor

perfect square formula

squared difference formula

(a b)^2=a^2 2ab b^2

(a b)(a-b)=a^2-b^2