Mathematics
Grade 9
15 min
Multiply by 5
Multiply by 5
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Multiply a polynomial expression by 5 using the distributive property.
Multiply a radical expression by 5 and correctly simplify the result.
Define the function g(x) = 5f(x) given a function f(x) in quadratic or linear form.
Describe the graphical transformation that occurs when a function f(x) is multiplied by 5.
Apply the concept of multiplying by 5 to solve algebraic equations involving parentheses.
Differentiate between multiplying a function by 5 and evaluating a function at 5x.
How can a simple operation like multiplying by 5 completely change the shape of a parabola or the outcome of a physics equation? 🚀
In this lesson, we'll elevate the basic concept of 'multiplying by 5' to a Grade 9 algebraic level. You will learn how this oper...
2
Key Concepts & Vocabulary
TermDefinitionExample
Scalar MultiplicationThe process of multiplying a mathematical object (like a polynomial, vector, or function) by a single number (a scalar). In this lesson, our scalar is 5.Multiplying the polynomial (x + 2) by the scalar 5 results in 5(x + 2) = 5x + 10.
Distributive PropertyA fundamental property of algebra which states that multiplying a sum by a number is the same as multiplying each addend by the number and then adding the products.5(a + b) = 5a + 5b. For the polynomial (x^2 - 3x), 5(x^2 - 3x) = 5x^2 - 15x.
CoefficientA numerical or constant quantity placed before and multiplying the variable in an algebraic expression.In the term 7x^2, the coefficient is 7. When we multiply this term by 5, we get 35x^2, and the new coefficient is 35.
Vertical StretchA transform...
3
Core Formulas
Multiplication over Polynomials
5 \cdot (ax^n + bx^{n-1} + \dots + c) = 5ax^n + 5bx^{n-1} + \dots + 5c
Use the distributive property to multiply the scalar 5 by the coefficient of every single term inside the polynomial.
Multiplication of Functions
Given a function f(x), the new function g(x) = 5f(x) is a vertical stretch of f(x) by a factor of 5.
To find the expression for the new function, enclose the entire expression for f(x) in parentheses and multiply it by 5.
Multiplication of Radical Expressions
5 \cdot (a\sqrt{b} + c\sqrt{d}) = 5a\sqrt{b} + 5c\sqrt{d}
The scalar 5 multiplies only the coefficients outside the radical signs. The radicands (the numbers inside the square roots) remain unchanged.
4 more steps in this tutorial
Sign up free to access the complete tutorial with worked examples and practice.
Sign Up Free to ContinueSample Practice Questions
Easy
Which property of algebra is primarily used when multiplying a polynomial like (x^2 + 3x - 7) by 5?
A.Associative Property
B.Commutative Property
C.Distributive Property
D.Identity Property
Easy
What is the result of multiplying the expression (x - 8) by 5?
A.5x - 40
B.5x - 8
C.x - 40
D.5x + 40
Easy
How do you correctly multiply the radical expression 7√3 by 5?
A.35√15
B.7√15
C.12√3
D.35√3
Want to practice and check your answers?
Sign up to access all questions with instant feedback, explanations, and progress tracking.
Start Practicing Free