How do you expand 3(x+5)? Algebra Polynomials and Factoring Multiplication of Monomials by Polynomials 1 Answer smendyka Nov 14, 2016 3x+15 Explanation: To expand 3(x+5) you distribute or multiple each term within the parenthesis by the term out side the parenthesis, in this case 3. 3(x+5)⇒(3×x)+(3×5)⇒3x+15 Answer link Related questions What is Multiplication of Monomials by Polynomials? How do you multiply monomials by polynomials? How do you multiply monomials by monomials? How do you multiply (3xy5)(−6x4y2)? How do you multiply and simplify 6ab(−10a2b3+c5)? How do you simplify −3a2b(9a2−4b2)? How do you multiply y(xy4)? How do you multiply (2x−1)(x3−2x2+3x−4)? How do you multiply (5n2)(2n5−2n33n7)? How do you simplify 2t2+(3+5)(4t)? See all questions in Multiplication of Monomials by Polynomials Impact of this question 21248 views around the world You can reuse this answer Creative Commons License