McGraw Hill Glencoe Algebra 2, 2012
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McGraw Hill Glencoe Algebra 2, 2012 View details
5. Operations with Radical Expressions
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Exercise 5 Page 419

To simplify the expression, use the Product Property of Radicals.

60x

Practice makes perfect

Before multiplying the given radical expressions, we need to answer two questions.

  1. Can the expressions be multiplied?
  2. If so, do absolute value symbols need to be added to the answer?

The Product Property of Radicals states that if sqrt(a) and sqrt(b) are real numbers, then sqrt(a)*sqrt(b) = sqrt(a b). 5sqrt(2x)* 3sqrt(8x)=5 * 3sqrt(2x* 8x) Because we assume that both radicals are real numbers and we can see that the given expressions have the same index, we can multiply them. Now, to answer the second question, consider the rule regarding absolute value symbols. sqrt(a^n)= a if n is odd |a| if n is even Since both radicals are real numbers and the roots are even, the expressions underneath the radicals are positive. Otherwise, the radicals would be imaginary. With this in mind, let's consider the possible values of the variable x.

  • In the both radicals, the index is even and the exponent of x is odd. Therefore, in order for this radical expression to result in a real number, x must be positive.

This means that if we remove x from the radical, we will not need absolute value symbols.

5sqrt(2x)* 3sqrt(8x)
5* 3* sqrt(2x)*sqrt(8x)
5 * 3* sqrt(2x * 8x)
15sqrt(16 x* x)
15sqrt(16x^2)

Next, let's simplify the radical expression by finding all of the perfect squares inside the radical.

15sqrt(16x^2)
15sqrt(4^2x^2)
15sqrt((4x)^2)
15 * 4x
60x