Solve Fifth Root Expression: Multiplying ∛(3³) and ∛(3²)

Question

Solve the following exercise:

335325= \sqrt[5]{3^3}\cdot\sqrt[5]{3^2}=

Video Solution

Solution Steps

00:00 Simplify the expression
00:03 The Cth root of number A to the power of B
00:06 The result will be equal to number A to the power of B divided by C
00:10 We will use this formula in our exercise
00:14 When multiplying powers with equal bases
00:17 The power of the result equals the sum of the powers
00:21 We will use this formula in our exercise, and add the powers
00:36 And this is the solution to the question

Step-by-Step Solution

In order to simplify the given expression, we will use two laws of exponents:

a. The root law (expanded):

amn=amn=(an)m \sqrt[\textcolor{blue}{n}]{a^{\textcolor{red}{m}}}=a^{\frac{\textcolor{red}{m}}{\textcolor{blue}{n}}} =(\sqrt[\textcolor{blue}{n}]{a})^{\textcolor{red}{m}}

b. The law of exponents for multiplication between terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n}

We'll start by converting the roots to exponent notation using the law of exponents mentioned in a':

335325=335325= \sqrt[\textcolor{blue}{5}]{3^{\textcolor{red}{3}}}\cdot\sqrt[\textcolor{blue}{5}]{3^{\textcolor{red}{2}}}= \\ \downarrow\\ 3^{\frac{\textcolor{red}{3}}{\textcolor{blue}{5}}}\cdot3^{\frac{\textcolor{red}{2}}{\textcolor{blue}{5}}} =

We'll continue, since we are multiplying two terms with identical bases - we'll use the law of exponents mentioned in b':

335325=335+25= 3^{\frac{3}{5}}\cdot3^{\frac{2}{5}}= \\ 3^{\frac{3}{5}+\frac{2}{5}}=

We'll continue and perform (separately) the addition of fractions in the exponent of the expression we got, we'll do this by expanding each of the fractions to the common denominator - the number 5, then we'll perform the multiplication and addition operations in the fraction numerator:

35+25=3+25=55=1 \frac{3}{5}+\frac{2}{5}=\\ \frac{3+2}{5}=\\ \frac{5}{5}=\\ 1

Therefore, we get:

335+25=31=3 3^{\frac{3}{5}+\frac{2}{5}}=\\ 3^{1}=\\ \boxed{3}

Let's summarize the expression simplification process:

335325=335+25=3 \sqrt[5]{3^3}\cdot\sqrt[5]{3^2}= \\ \downarrow\\ 3^{\frac{3}{5}+\frac{2}{5}}=\\ \boxed{3}

Therefore, the correct answer is answer a.

Answer

3 3