Question 149·Medium·Equivalent Expressions
Which expression is equivalent to , where and ?
For exponent simplification questions, first separate products inside parentheses, then apply the power-to-a-power rule to each factor. Carefully compute fractional and negative exponents, and at the end, rewrite any negative exponents by moving those factors to the denominator (or numerator) with positive exponents. This systematic approach is faster and less error-prone than trying to manipulate everything mentally at once.
Hints
Separate the product inside the parentheses
Think of as each factor and being raised to the 6th power.
Use the power-to-a-power rule
When you have , the new exponent is . Apply this idea to both and .
Handle the negative exponent carefully
After you multiply the exponents, if you get a negative exponent on , recall how to rewrite a negative exponent as a positive one in a fraction.
Desmos Guide
Compute the value of the original expression numerically
In Desmos, type the expression with specific positive values for and , such as:
Note the decimal value Desmos gives for this.
Compare each answer choice with the original value
On separate lines, enter each choice using the same and values, for example:
Identify which one gives exactly the same decimal value as the original expression; that choice is the equivalent expression.
Step-by-step Explanation
Distribute the outer exponent to each factor
Use the rule .
So,
Multiply exponents when raising a power to a power
Use the rule .
Apply it to each factor:
Compute the products in the exponents:
So the expression becomes
Rewrite the negative exponent as a fraction
Use the rule .
From , the factor moves to the denominator with a positive exponent:
So the equivalent expression is .