Find Expressions Equivalent to 8x²+4x: Polynomial Practice

Polynomial Factoring with Greatest Common Factor

Which of the expressions is equivalent to the expression?

8x2+4x 8x^2+4x

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Take out common factor
00:03 Break down 8 into factors 4 and 2
00:07 Break down the square into products
00:13 Mark the common factors
00:24 Extract the common factors from the parentheses
00:30 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

Which of the expressions is equivalent to the expression?

8x2+4x 8x^2+4x

2

Step-by-step solution

Let's solve the problem step by step:

  • Step 1: Identify the greatest common factor (GCF) of the coefficients in the expression 8x2+4x8x^2 + 4x. The numbers are 8 and 4, and the GCF is 4.

  • Step 2: Factor out the common variable. Both terms have xx as a common variable factor, so the GCF of the variable part is xx.

  • Step 3: Factor the expression using the GCF. We take 4x4x as a common factor from both terms:
    8x28x^2 can be rewritten as 4x2x4x \cdot 2x.
    +4x+4x can be rewritten as 4x14x \cdot 1.

  • Step 4: Write the factored expression:
    8x2+4x=4x(2x+1)8x^2 + 4x = 4x(2x + 1).

  • Step 5: Verify by checking each option. The expression we obtained 4x(2x+1)4x(2x + 1) matches the choice with 2.

Therefore, the equivalent expression is 4x(2x+1)4x(2x+1).

3

Final Answer

4x(2x+1) 4x(2x+1)

Key Points to Remember

Essential concepts to master this topic
  • GCF Rule: Find greatest common factor of coefficients and variables
  • Technique: Factor out 4x from 8x2+4x=4x(2x+1) 8x^2 + 4x = 4x(2x + 1)
  • Check: Distribute back: 4x(2x + 1) = 8x² + 4x ✓

Common Mistakes

Avoid these frequent errors
  • Factoring out only part of the GCF
    Don't factor out just 4 and leave x behind = incomplete factoring like 4(2x² + x)! This misses the common x factor and doesn't fully simplify. Always factor out the complete GCF including all common variables.

Practice Quiz

Test your knowledge with interactive questions

Break down the expression into basic terms:

\( 4x^2 + 6x \)

FAQ

Everything you need to know about this question

How do I find the GCF of coefficients and variables together?

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Find the GCF of numbers separately, then the lowest power of each variable. For 8x2+4x 8x^2 + 4x : GCF of 8 and 4 is 4, lowest power of x is x¹, so GCF = 4x.

What if I can't see the common factor right away?

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List the prime factorization of each term! For example: 8x2=23x2 8x^2 = 2^3 \cdot x^2 and 4x=22x 4x = 2^2 \cdot x . The common factors are 22x=4x 2^2 \cdot x = 4x .

How do I know my factoring is correct?

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Always distribute back to check! Multiply 4x(2x+1)=4x2x+4x1=8x2+4x 4x(2x + 1) = 4x \cdot 2x + 4x \cdot 1 = 8x^2 + 4x . If you get the original expression, you're right!

Can I factor this expression differently?

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You could factor out smaller amounts like 2x(4x+2) 2x(4x + 2) , but it's not fully factored. Always factor out the greatest common factor to get the simplest form.

What if one of the answer choices looks close but not exact?

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Be careful! Expand each choice to double-check. For example, 4x(2x+6)=8x2+24x 4x(2x + 6) = 8x^2 + 24x which is NOT equal to 8x2+4x 8x^2 + 4x .

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