Solve the Expression: Finding 7^1 - 7^2

Exponent Evaluation with Negative Results

Solve the following exercise:

7172= 7^1-7^2=

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Solve the following expression
00:04 Break down the exponents
00:12 Always solve multiplication and division before addition and subtraction
00:19 Continue to solve the expression according to the correct order of operations, from left to right
00:23 This is the solution

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Solve the following exercise:

7172= 7^1-7^2=

2

Step-by-step solution

To solve the expression 7172 7^1 - 7^2 , we need to evaluate the powers first before performing the subtraction. The steps are as follows:

  • Calculate 71 7^1 : Since any number to the power of 1 is the number itself, we have 71=7 7^1 = 7 .
  • Calculate 72 7^2 : This means 7 is multiplied by itself, which gives us 7×7=49 7 \times 7 = 49 .
  • Subtract the results: Now, perform the subtraction 749 7 - 49 .
  • This yields: 749=42 7 - 49 = -42 .

Thus, the correct answer is 42 -42 .

3

Final Answer

42 -42

Key Points to Remember

Essential concepts to master this topic
  • Rule: Always calculate exponents before performing subtraction operations
  • Technique: Evaluate 71=7 7^1 = 7 and 72=49 7^2 = 49 first
  • Check: Substitute back: 749=42 7 - 49 = -42 matches our answer ✓

Common Mistakes

Avoid these frequent errors
  • Performing subtraction before evaluating exponents
    Don't subtract the exponents like 7^(1-2) = 7^(-1) = 1/7! This ignores order of operations and gives a completely wrong result. Always evaluate each exponent first, then perform the subtraction operation.

Practice Quiz

Test your knowledge with interactive questions

What is the result of the following equation?

\( 36-4\div2 \)

FAQ

Everything you need to know about this question

Why is the answer negative when both numbers are positive?

+

Great question! Even though 7 is positive, we're subtracting a larger number (49) from a smaller one (7). Whenever you subtract a larger number from a smaller one, the result is negative: 749=42 7 - 49 = -42 .

Do I need to follow order of operations here?

+

Yes, absolutely! Remember PEMDAS: Parentheses, Exponents, Multiplication/Division, Addition/Subtraction. Since exponents come before subtraction, calculate 71 7^1 and 72 7^2 first, then subtract.

What does 7^1 equal and why?

+

Any number raised to the power of 1 equals itself. So 71=7 7^1 = 7 . This is because you're multiplying the base by itself 1 time, which is just the number itself!

How do I calculate 7^2 without a calculator?

+

72 7^2 means 7 × 7. You can break it down: 7×7=(5+2)×7=35+14=49 7 \times 7 = (5 + 2) \times 7 = 35 + 14 = 49 . Practice your multiplication tables to make this faster!

Could the answer be positive instead?

+

No, the answer must be negative. Since we're calculating 749 7 - 49 , we're subtracting 49 from 7. This always gives -42, not +42. The order matters in subtraction!

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Powers and Roots - Basic questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations