Simplify x² - 5⅕x²: Subtracting Like Terms with Mixed Numbers

Algebraic Subtraction with Mixed Number Coefficients

(+x2)(515x2)= (+x^2)-(5\frac{1}{5}x^2)=

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00:00 Simply
00:02 Negative times positive is always negative
00:06 Collecting terms
00:09 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

(+x2)(515x2)= (+x^2)-(5\frac{1}{5}x^2)=

2

Step-by-step solution

To solve this problem, we'll follow these steps:

  • Step 1: Understand the problem components - recognize the operation between two terms involving x2x^2.
  • Step 2: Convert mixed numbers to improper fractions if needed and focus on calculating the coefficients.
  • Step 3: Perform the subtraction operation.
  • Step 4: Write the result as a coefficient of x2x^2.

Now, let's work through each step:

Step 1: The expression involves the subtraction of (+x2)(+x^2) and (515x2)(5\frac{1}{5}x^2).

Step 2: Convert 5155\frac{1}{5} into an improper fraction. This gives us 265\frac{26}{5}.

Step 3: Subtract the coefficients:

  • 12651 - \frac{26}{5} (Recall that +x2+x^2 is equivalent to 1x21x^2)

Converting 1 into a fraction: 55\frac{5}{5}. Thus, we have:

55265=5265\frac{5}{5} - \frac{26}{5} = \frac{5 - 26}{5}

This simplifies to:

215\frac{-21}{5}

Step 4: Attach this result to x2x^2. Hence, the expression simplifies to:

215x2-\frac{21}{5}x^2

In mixed number form, this is 415x2-4\frac{1}{5}x^2.

Therefore, the solution to the problem is 415x2 -4\frac{1}{5}x^2 .

3

Final Answer

415x2 -4\frac{1}{5}x^2

Key Points to Remember

Essential concepts to master this topic
  • Like Terms Rule: Subtract coefficients when variables and powers match exactly
  • Mixed Numbers: Convert 515 5\frac{1}{5} to 265 \frac{26}{5} before calculating
  • Verification: Check that 1265=215=415 1 - \frac{26}{5} = -\frac{21}{5} = -4\frac{1}{5}

Common Mistakes

Avoid these frequent errors
  • Adding instead of subtracting coefficients
    Don't change 1515 1 - 5\frac{1}{5} to 1+515=615 1 + 5\frac{1}{5} = 6\frac{1}{5} ! The subtraction sign applies to the entire second term including its coefficient. Always keep the operation sign and subtract: 1265=215 1 - \frac{26}{5} = -\frac{21}{5} .

Practice Quiz

Test your knowledge with interactive questions

a is negative number.

b is negative number.

What is the sum of a+b?

FAQ

Everything you need to know about this question

Why do I need to convert the mixed number to an improper fraction?

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Converting 515 5\frac{1}{5} to 265 \frac{26}{5} makes subtraction easier! With improper fractions, you can find a common denominator and subtract directly: 55265=215 \frac{5}{5} - \frac{26}{5} = \frac{-21}{5} .

How do I know these are like terms that can be combined?

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Both terms have exactly the same variable part: x2 x^2 . When the variables and their exponents match perfectly, you can combine the coefficients. Think of it as 1 apple minus 5⅕ apples!

Can I subtract the whole number and fraction parts separately?

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No! You must treat 515 5\frac{1}{5} as one complete number. Convert to 265 \frac{26}{5} first, then subtract from 1. Separating the parts leads to incorrect answers.

Why is my answer negative?

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You're subtracting a larger number from a smaller one! Since 1<515 1 < 5\frac{1}{5} , the result 1515 1 - 5\frac{1}{5} must be negative. This is perfectly normal in algebra.

How do I convert my improper fraction answer back to a mixed number?

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Divide the numerator by the denominator: 215=21÷5=4 \frac{-21}{5} = -21 ÷ 5 = -4 remainder 1 1 . So 215=415 \frac{-21}{5} = -4\frac{1}{5} . The negative sign applies to the entire mixed number.

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