Mathematics
Grade 11
15 min
Multiply radical expressions
Multiply radical expressions
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1
Introduction & Learning Objectives
Learning Objectives
Multiply monomial radical expressions and simplify the result.
Apply the distributive property to multiply a monomial by a polynomial radical expression.
Use the FOIL method to multiply two binomial radical expressions.
Identify and multiply conjugate radical expressions to simplify the product.
Simplify the product of radical expressions by identifying and extracting perfect nth roots.
Solve multi-step problems involving the multiplication of radicals with both numerical and variable radicands.
Ever wondered how engineers calculate the vibrations in a bridge or how game developers create realistic physics? 🎮 It often involves multiplying complex radical expressions!
This tutorial will guide you through the process of multiplying radical expressions, fr...
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Key Concepts & Vocabulary
TermDefinitionExample
Radical ExpressionAn expression that contains a root (square root, cube root, etc.). The symbol for the root is called the radical sign (√).5√3, √(2x), and ∛(y-1) are all radical expressions.
RadicandThe number or expression found inside the radical symbol.In the expression √18, the radicand is 18.
IndexThe degree of the root. It's the small number written to the left of the radical symbol. If no index is written, it is assumed to be 2 (a square root).In ∛8, the index is 3.
Like RadicalsRadical expressions that have the same index and the same radicand. These are the only types of radicals that can be combined through addition or subtraction.7√5 and -2√5 are like radicals. 7√5 and 7∛5 are not.
Simplest Radical FormA radical is in simplest form when: 1) The radic...
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Core Formulas
Product Rule for Radicals
\sqrt[n]{a} \cdot \sqrt[n]{b} = \sqrt[n]{ab}
To multiply two radical expressions with the same index (n), multiply their radicands (a and b) together under a single radical with the same index. This is the fundamental rule for all radical multiplication.
Distributive Property
a(b + c) = ab + ac
This property is used to multiply a single radical term (a monomial) by a radical expression with two or more terms (a polynomial). You multiply the outside term by each term inside the parentheses.
Product of Conjugates
(a + b)(a - b) = a^2 - b^2
This special product pattern is extremely useful for multiplying binomial radical expressions that are conjugates. The multiplication results in the square of the first term minus the square of the second te...
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Challenging
Simplify the expression: \((\sqrt{15} - \sqrt{6})(\sqrt{5} + \sqrt{2})\).
A.\(\sqrt{75} - \sqrt{12}\)
B.\(3\sqrt{3}\)
C.\(7\sqrt{3}\)
D.\(5\sqrt{3} + \sqrt{30} - \sqrt{30} - 2\sqrt{3}\)
Challenging
Multiply and simplify: \((\sqrt{3} + 2)(\sqrt{27} - 2\sqrt{3} + 1)\).
A.\(5 + 3\sqrt{3}\)
B.\(9 - 4\sqrt{9} + 2\)
C.\(4 + 5\sqrt{3}\)
D.\(11 + 3\sqrt{3}\)
Challenging
Simplify the expression \((2\sqrt{x} + \sqrt{y})^2 - (2\sqrt{x} - \sqrt{y})^2\), assuming \(x, y \ge 0\).
A.0
B.\(2y\)
C.\(8x + 2y\)
D.\(8\sqrt{xy}\)
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