Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

How to Subtract Polynomials: Rules and Examples for Students

ffImage
hightlight icon
highlight icon
highlight icon
share icon
copy icon
SearchIcon
widget title icon
Latest Updates

What Is the First Step in Subtracting Polynomials?

Subtracting polynomials plays a crucial role in both exam preparation and real-life algebra tasks, such as simplifying expressions or solving equations. Mastering this skill helps students handle board exam questions quickly and with fewer mistakes. Clear understanding boosts confidence in tough math topics and lays a foundation for more advanced studies.


Formula Used in Subtracting Polynomials

The standard formula is:

[P(x)Q(x)]=P(x)+[Q(x)]
, where you change the sign of each term in the second polynomial and then add like terms.


Here’s a helpful table to understand subtracting polynomials more clearly:


Subtracting Polynomials Table

StepActionReason
1 Arrange polynomials in standard form Aligns like terms
2 Change sign of each term in second polynomial Converts subtraction to addition
3 Combine like terms Simplifies the expression

This table highlights how subtracting polynomials follows a clear pattern in every algebraic calculation.


Worked Example – Solving a Problem

Let’s subtract two polynomials step by step:

1. Write the problem: Subtract
4x23x+6
from $7x^2 + 2x - 5$

2. Arrange in standard form (already arranged):
(7x2+2x5)(4x23x+6)

3. Change the sign of each term in the second polynomial:
7x2+2x54x2+3x6

4. Combine like terms by powers:
(7x24x2)+(2x+3x)+(56)

5. Final calculation:
3x2+5x11

Final Answer:

3x2+5x11


For deeper understanding and extra practice, visit our polynomials worksheets page and try more examples. If you want foundation concepts, check our resource on polynomial basics.


Practice Problems

  • Subtract
    (2x3+5x4)
    from
    (7x32x+6)
    .
  • Find the result of
    (3x2+x9)(x25x+3)
    .
  • Subtract
    (4x7)
    from
    (11x+3)
    .
  • Subtract
    (5y24y+10)
    from
    (2y2+6y7)
    .

Practice with the above to master subtracting polynomials. For help on related terms like coefficients and factors, see our expression, term, factor, and coefficient guide.


Common Mistakes to Avoid

  • Forgetting to change all signs in the second polynomial when subtracting.
  • Mismatching like terms—always pair terms with the same powers.
  • Skipping arrangement into standard form before starting.

Understanding this helps you avoid errors in both homework and competitive exams. Related confusion between addition and subtraction rules? See adding and subtracting algebraic expressions for clarity.


Real-World Applications

Subtracting polynomials helps in fields like engineering, economics, and science where you need to analyze changes or find differences between mathematical models. At Vedantu, we link these skills to practical scenarios so students recognize their value beyond just exams.


More algebra topics are connected to this, such as algebraic expressions, which form the foundation for polynomial subtraction, and factoring polynomials, where subtraction often appears in formula transformations.


We explored the idea of subtracting polynomials, learned step-wise subtraction, common pitfalls, and saw how these skills empower students for exams and real-world use. Keep practicing with Vedantu for even stronger algebra abilities!


FAQs on How to Subtract Polynomials: Rules and Examples for Students

1. What is the rule for adding and subtracting polynomials?

Adding and subtracting polynomials involves combining like terms by focusing on terms with the same variable and exponent. When adding, simply add the coefficients of like terms. When subtracting, distribute the negative sign and then add the coefficients as with addition.

2. How do you find the difference between two polynomials?

To find the difference between two polynomials:
1. Write both polynomials in standard form (highest degree first).
2. Place parentheses around the polynomial to be subtracted.
3. Change the sign of each term in the second polynomial by distributing the negative sign.
4. Add like terms to simplify the result.

3. When subtracting polynomials, the first step is to?

The first step in subtracting polynomials is to place parentheses around the polynomial you want to subtract and then distribute the minus sign to each term inside the parentheses. This changes the signs of all terms in the second polynomial before combining like terms.

4. How do you subtract polynomials in math is fun?

On 'Math is Fun,' to subtract polynomials:
- Write both polynomials, making sure like terms are aligned.
- Change the sign of each term in the second polynomial (the one being subtracted).
- Add the coefficients of like terms to find the answer.

5. What are some steps for subtracting polynomials?

Steps to subtract polynomials:
1. Arrange both polynomials in descending order of degree.
2. Place parentheses around the second polynomial and apply the negative sign.
3. Remove parentheses by changing the signs of the second polynomial's terms.
4. Combine like terms to get the simplified answer.

6. Can you give an example of subtracting polynomials?

Example:
Subtract (3x2 + 2x - 5) from (5x2 - 4x + 7).
Step 1: (5x2 - 4x + 7) - (3x2 + 2x - 5)
Step 2: 5x2 - 4x + 7 - 3x2 - 2x + 5
Step 3: (5x2 - 3x2) + (-4x - 2x) + (7 + 5)
Final Answer: 2x2 - 6x + 12

7. How do you subtract polynomials with exponents?

Subtracting polynomials with exponents works the same as standard subtraction: match and subtract the coefficients of like terms (same variable, same exponent), and write the result in standard form.

8. Can you subtract polynomials with fractions?

Yes, you can subtract polynomials with fractional coefficients. Treat the fractions just as you would in any addition or subtraction, finding a common denominator if needed before combining like terms.

9. Are there worksheets available for practicing subtracting polynomials?

Yes, several online resources offer subtracting polynomials worksheets in printable PDF format, including sample problems with solutions to support student practice and concept reinforcement.

10. Is there a calculator for subtracting polynomials?

Yes, there are free online subtracting polynomials calculators that allow you to input two polynomials and receive the simplified difference instantly, showing all necessary steps.

11. What is the difference between adding and subtracting polynomials?

The main difference is that in adding polynomials you directly add the coefficients of like terms, while in subtracting polynomials you change the sign of each term in the polynomial to be subtracted before adding the like terms.

12. What should students remember when subtracting polynomials for exams?

Students should remember to align like terms, carefully change the signs of the second polynomial, and combine like terms properly. Always double-check calculations and write the final answer in standard form, as required in CBSE exams.