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MATH 1150 · Radical expressions · Objective 1.5

Simplify Before Adding or Subtracting Radicals

Reveal hidden like radicals by simplifying every term first.

CLO 1 · Topic 21 of 21
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Build the concept from the beginning

Meaning before procedure

Radicals that look unlike may become like after perfect-power factors are extracted. The correct order is simplify each radical, then group matching radical parts, then combine coefficients.

Hidden like radicals
Different original radicands that simplify to the same radical part.
Term-by-term simplification
Simplify each radical without crossing addition signs.
Coefficient product
Multiply original and extracted coefficients.
Final collection
Combine only after forms are simplified.

Interactive visual model

Simplify hidden like radicals, then combine their coefficients.

Change one control at a time and describe what changes—and what stays invariant.

A dependable four-step method

Simplify each radical term independently.
Multiply extracted factors by existing coefficients.
Identify matching simplified radical parts.
Combine coefficients and verify no further simplification remains.
  1. Simplify each radical term independently.
  2. Multiply extracted factors by existing coefficients.
  3. Identify matching simplified radical parts.
  4. Combine coefficients and verify no further simplification remains.
Three fully explained examples

Watch the reasoning, not just the answer

Example 1: Simplify √8 + √18.

Name the goalFactor each radicand.
Choose the next move√8 = 2√2 and √18 = 3√2.
Carry out the mathematics2√2 + 3√2 = 5√2.
Check and interpretThe remaining radicand 2 is square-free.

Example 2: Simplify 3√12 − √27.

Name the goalSimplify both radicals first.
Choose the next move3√12 = 3·2√3 = 6√3; √27 = 3√3.
Carry out the mathematics6√3 − 3√3 = 3√3.
Check and interpretSquaring approximations confirms the original and final values agree.

Example 3: Simplify 2√50 + √8 − 3√2.

Name the goalAll terms can use √2.
Choose the next move2√50 = 10√2 and √8 = 2√2.
Carry out the mathematics10√2 + 2√2 − 3√2 = 9√2.
Check and interpretThe coefficient arithmetic is 10 + 2 − 3 = 9.
Interactive practice

Predict, decide, check, and revise

Interactive construction lab

Build a valid reasoning path

Choose the decisions in the order a careful solver would use them for this concept.

Choose this step, then check the construction.
Choose this step, then check the construction.
Choose this step, then check the construction.

The reasoning path changes as each decision is selected.

Readiness check

Check the foundation

Simplify √8+√18.

Simplify √12+√27.

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Guided practice

Apply the method with support

Simplify √20+√45.

Simplify 2√8+√50.

Simplify 3√12−√27.

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Independent practice

Work without step prompts

Simplify √75−√12.

Simplify 2√18+3√8.

Simplify √48+√75.

Simplify 3√20−2√45.

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Mastery check

Demonstrate durable understanding

Simplify √98−√8.

Simplify 2√27+√12.

Simplify √32+2√50−3√2.

Simplify 4√12−√75.

Simplify 2√45+√80.

Not completed yet.
Unfamiliar transfer

Explain, compare, and revise

A rectangle has side lengths √75 and 2√12. Find its perimeter in simplest radical form.

Write a first attempt before opening the self-check.

The learner record reveals exact answers and model reasoning only after an attempt.