Multiply Cube Roots: Solving ∛(2²) × ∛2 Step by Step

Question

Solve the following exercise:

22323= \sqrt[3]{2^2}\cdot\sqrt[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 equal number A to the power of B divided by C
00:09 Every number is essentially to the power of 1
00:12 We will use this formula in our exercise
00:15 When multiplying powers with equal bases
00:20 The power of the result equals the sum of the powers
00:24 We will use this formula in our exercise, and add the powers
00:33 And this is the solution to the question

Step-by-Step Solution

To simplify the given expression we use two laws of exponents:

A. The law of roots (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 of terms with identical bases:

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

Let's start from the root level to write exponents using the law of exponents shown in A:

22323=223213=223213= \sqrt[\textcolor{blue}{3}]{2^{\textcolor{red}{2}}}\cdot\sqrt[\textcolor{blue}{3}]{2}= \\ \sqrt[\textcolor{blue}{3}]{2^{\textcolor{red}{2}}}\cdot\sqrt[\textcolor{blue}{3}]{2^{\textcolor{red}{1}}}= \\ \downarrow\\ 2^{\frac{\textcolor{red}{2}}{\textcolor{blue}{3}}}\cdot2^{\frac{\textcolor{red}{1}}{\textcolor{blue}{3}}} =

We continue, since multiplication is performed between two terms with identical bases - we use the law of exponents shown in B:

223213=223+13= 2^{\frac{2}{3}}\cdot2^{\frac{1}{3}}= \\ 2^{\frac{2}{3}+\frac{1}{3}}=

We continue and perform (separately) the operation of combining the numerators in the exponent fraction that was obtained, this is done by expanding each of the numerators to the common denominator - the number 3, then we perform the addition and subtraction operations in the numerator of the fraction:

23+13=2+13=33=1 \frac{2}{3}+\frac{1}{3}=\\ \frac{2+1}{3}=\\ \frac{3}{3}=\\ 1

In other words - we get that:

223+13=21=2 2^{\frac{2}{3}+\frac{1}{3}}=\\ 2^{1}=\\ \boxed{2}

Let's summarize the process of simplifying the expression:

22323=223+13=2 \sqrt[3]{2^2}\cdot\sqrt[3]{2}= \\ \downarrow\\ 2^{\frac{2}{3}+\frac{1}{3}}=\\ \boxed{2}

Therefore, the correct answer is answer A.

Answer

2 2