Example

Simplifying 518285\sqrt{18} - 2\sqrt{8}

Simplify the expression 518285\sqrt{18} - 2\sqrt{8}, where both terms already have numerical coefficients and the radicals must also be simplified.

Simplify each radical by extracting the largest perfect square factor:

518=592=532=1525\sqrt{18} = 5 \cdot \sqrt{9} \cdot \sqrt{2} = 5 \cdot 3 \cdot \sqrt{2} = 15\sqrt{2}

28=242=222=422\sqrt{8} = 2 \cdot \sqrt{4} \cdot \sqrt{2} = 2 \cdot 2 \cdot \sqrt{2} = 4\sqrt{2}

In each case, the Associative Property of Multiplication allows the original coefficient and the integer from the simplified radical to be multiplied together into a single new coefficient.

Rewrite the expression:

1524215\sqrt{2} - 4\sqrt{2}

Both terms contain 2\sqrt{2}, so combine the coefficients: 154=1115 - 4 = 11.

51828=1125\sqrt{18} - 2\sqrt{8} = 11\sqrt{2}

This example demonstrates that when each term already carries a coefficient, the simplification process produces a product of three factors — the original coefficient, the integer from the simplified radical, and the remaining radical — which are then consolidated using the Associative Property before combining like radicals.

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Updated 2026-04-21

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