Question 1
Which expression is the correct simplification of ?No clue? Show me the answer
Correct answer
Correct!
IncorrectStep-by-step walkthrough
Choose a solution method
Method #1Direct ApproachStep 1: Identify the law to apply
We are multiplying two powers with the same base (5). This calls for the Product Rule: .
Step 2: Add the exponents
Keep the base as 5 and add the exponents:
Step 3: State the answer
The simplified expression is . The base stays as 5 — it does not get multiplied.
Method #2Process of EliminationStep 1: Identify what is being asked
We need to simplify using exponent laws. The key question is: what happens to the base and exponents when multiplying same-base powers?
Step 2: Eliminate $5^{18}$
The option would result from multiplying the exponents (). That rule applies to a power of a power like , not a product. So this is wrong.
Step 3: Eliminate $25^9$
The option multiplies both the base () and adds the exponents. This is a double error — the base must stay as 5, not change to 25.
Step 4: Eliminate $5^{15}$
The option does not match any standard rule here. , not 15. This value has no logical basis.
Step 5: Select the correct answer
The correct answer is , found by applying the product rule: .
Question 2
A student simplifies and gets . Which exponent law did the student use?No clue? Show me the answer
Correct answer
Correct!
IncorrectStep-by-step walkthrough
Choose a solution method
Method #1Direct ApproachStep 1: Identify the operation
The expression is a division (a fraction) of two powers with the same base. This matches the Quotient Rule.
Step 2: Apply the Quotient Rule
The Quotient Rule states . So:
Step 3: Confirm the law used
The student subtracted the exponents (), which is exactly the Quotient Rule.
Method #2Process of EliminationStep 1: Identify what is being asked
We need to identify which law produces the result from .
Step 2: Eliminate the Product Rule
The Product Rule applies to multiplication, giving . Here we have division, not multiplication, so this law does not apply.
Step 3: Eliminate the Power of a Power Rule
The Power of a Power Rule applies to expressions like , where a power is raised to another power. This is a division expression, so that rule is irrelevant.
Step 4: Eliminate the Zero Exponent Rule
The Zero Exponent Rule tells us that . Since the result is , not 1, this rule is not what was used.
Step 5: Select the correct answer
The correct law is the Quotient Rule: , giving .
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