Example

Simplifying 20+35\sqrt{20} + 3\sqrt{5}

Simplify the expression 20+35\sqrt{20} + 3\sqrt{5}, where one of the square roots must be simplified before the terms can be combined.

The two terms do not initially appear to be like radicals because their radicands (2020 and 55) are different. Simplify 20\sqrt{20} by extracting its largest perfect square factor:

20=45=45=25\sqrt{20} = \sqrt{4 \cdot 5} = \sqrt{4} \cdot \sqrt{5} = 2\sqrt{5}

Now rewrite the original expression with the simplified radical:

25+352\sqrt{5} + 3\sqrt{5}

Both terms contain 5\sqrt{5}, so they are like radicals. Combine the coefficients: 2+3=52 + 3 = 5.

20+35=55\sqrt{20} + 3\sqrt{5} = 5\sqrt{5}

This example illustrates that a radical expression which appears to contain unlike terms may actually contain like radicals once each square root has been simplified.

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Updated 2026-04-21

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