Question Video: Computing Numerical Expressions Involving Square Roots | Nagwa Question Video: Computing Numerical Expressions Involving Square Roots | Nagwa

Question Video: Computing Numerical Expressions Involving Square Roots Mathematics • Second Year of Preparatory School

Express ((−√3)³ × (−√2)²)² in its simplest form.

03:24

Video Transcript

Express the square of negative square root of three cubed multiplied by negative square root of two squared in its simplest form.

To simplify this expression, we need to recall and apply the relevant laws of exponents. First, we apply the power of a product rule, which states that for real numbers 𝑎 and 𝑏 and integer 𝑛, the product of 𝑎 and 𝑏 to the power of 𝑛 is equal to 𝑎 to the power of 𝑛 multiplied by 𝑏 to the power of 𝑛. This means we can rewrite our expression as negative square root of three cubed to the power of two multiplied by negative square root of two squared to the power of two.

Next, we apply the power of a power rule, which says for real number 𝑎 and integers 𝑚 and 𝑛, 𝑎 to the power of 𝑚 to the power of 𝑛 is equal to 𝑎 to the power of 𝑚 times 𝑛. This means we can write our expression as negative square root of three to the power of six multiplied by negative square root of two to the power of four.

At this point, we may be tempted to use the product rule, which says that for real number 𝑎 and integers 𝑚 and 𝑛, 𝑎 to the power of 𝑚 multiplied by 𝑎 to the power of 𝑛 is equal to 𝑎 to the power of 𝑚 plus 𝑛. But this would be a mistake, because the product rule only applies when the real number bases are the same.

We note that a negative square root is equal to negative one times the root. So we can use the power of a product rule to rewrite our expression as negative one to the power of six multiplied by square root of three to the power of six multiplied by negative one to the power of four multiplied by the square root of two to the power of four.

We recall that for any even integer 𝑚, negative one to the power of 𝑚 is equal to positive one. So negative one to the power of six equals one, and negative one to the power of four equals one. So we are left with the square root of three to the power of six multiplied by the square root of two to the power of four.

We recall that for an expression with a base 𝑎, where 𝑎 is positive, the square root of 𝑎 squared is equal to 𝑎. So we can write the square root of three to the power of six and the square root of two to the power of four as a product of powers of two using the product rule in reverse. This gives us the square root of three squared multiplied by the square root of three squared multiplied by the square root of three squared multiplied by the square root of two squared multiplied by the square root of two squared.

Since the square root of 𝑎 squared equals 𝑎, we have three times three times three times two times two. Therefore, the square of negative square root of three cubed multiplied by the negative square root of two squared simplifies to 108.

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