Multiply Square Roots: Solving √9 × √3 Step by Step

Solve the following exercise:

$\sqrt{9}\cdot\sqrt{3}=$

Although the square root of 9 is known (3) , in order to get a single expression we will use the laws of parentheses:

So- in order to simplify the given expression we will use two exponents laws:

A. Defining the root as a an exponent:

$\sqrt[n]{a}=a^{\frac{1}{n}}$B. Multiplying different bases with the same power (in the opposite direction):

$x^n\cdot y^n =(x\cdot y)^n$

Let's start by changing the square root into an exponent using the law shown in A:

$\sqrt{9}\cdot\sqrt{3}= \\ \downarrow\\ 9^{\frac{1}{2}}\cdot3^{\frac{1}{2}}=$Since a multiplication is performed between two bases with the same exponent we can use the law shown in B.

$9^{\frac{1}{2}}\cdot3^{\frac{1}{2}}= \\ (9\cdot3)^{\frac{1}{2}}=\\ 27^{\frac{1}{2}}=\\ \boxed{\sqrt{27}}$In the last steps we performed the multiplication, and then used the law of defining the root as an exponent shown earlier in A (in the opposite direction) in order to return to the root notation.

Therefore, the correct answer is answer C.