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Roots That Are Not Whole

Part of the Factoring & Quadratics section of Coddy's Algebra journey. Lesson 46 of 63.

x^2 = 5: no whole number squares to 5, but the equation still has two solutions. They are written with the radical sign: x = ±√5, the exact numbers whose squares are 5.

√5 is not a made-up dodge; it is a number a little over 2.2, living between √4 = 2 and √9 = 3. Exact answers keep the radical; a calculator can approximate it whenever a decimal is wanted.

So the root method never fails on x^2 = positive number: perfect squares give whole answers, the rest give radicals, and both are complete, correct solutions. What happens with a NEGATIVE number on the right is a different story, told two chapters from now.

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Challenge

Easy

Solve x^2 = 13 exactly.

Try it yourself

x^2 = 13

Solve for x

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