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Grade 12 · Math · Calculus

12th grade Limits that need factoring or rationalizing worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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Limits that need factoring or rationalizing

Grade 12 Math Worksheet - Building Confidence

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Circle the best answer, or write your answer on the line.

  1. Ari wants the limit of (x² + 3x − 10)/(x − 2) as x → 2. Direct substitution fails. What is the limit?

  2. Bo wants the limit of (x² + 2x − 15)/(x − 3) as x → 3. Direct substitution fails. What is the limit?

  3. Jun wants the limit of (x² − 7x + 10)/(x − 2) as x → 2. Direct substitution fails. What is the limit?

  4. After multiplying by the conjugate, Kira's limit as x → 3 became 1/(√(x + 1) + 2). What is the limit?

  5. After multiplying by the conjugate, Luz's limit as x → 0 became 1/(√(x + 9) + 3). What is the limit?

  6. After multiplying by the conjugate, Milo's limit as x → 9 became 1/(√(x + 7) + 4). What is the limit?

  7. After multiplying by the conjugate, Noah's limit as x → 9 became 1/(√(x + 16) + 5). What is the limit?

  8. Ren has the factored form (x + 2)(x + 5)/((x + 2)(x + 4)). What is its limit as x → -2?

  9. Tala has the factored form (x − 1)(x + 6)/((x − 1)(x − 3)). What is its limit as x → 1?

  10. Zee has the factored form (x − 4)(x − 1)/((x − 4)(x + 2)). What is its limit as x → 4?

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12th grade Limits that need factoring or rationalizing worksheet – printable
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About this worksheet

Limits that need factoring or rationalizing. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can factor and cancel to find a 0/0 limit.
  • I can use the conjugate to clear a square root, and combine fractions in a limit.
  • I can choose the first step for a limit and find the constant that makes it exist.

Standard: none (beyond CCSS)

Words to know

factor and cancel: Split top and bottom into factors and remove the shared one.

conjugate: √a + b for √a − b; their product has no square root.

difference quotient: (s(t) − s(a))/(t − a): an average speed between a and t.

Common mistakes

Read 0/0 as 0. 0/0 means the top and bottom share a factor; cancel it, then substitute again.

Read 0/0 as 1. 0/0 has no value of its own; cancel the shared factor first.

Dropped part of the new bottom after using the conjugate. √(x + 4) + 2 at x = 0 is 2 + 2.

Questions parents ask

What is the most common mistake with limits that need factoring or rationalizing?

Read 0/0 as 0. 0/0 means the top and bottom share a factor; cancel it, then substitute again.

Are these 12th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

More calculus

See all Calculus

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