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# Week 4 in PreCalc 11

But before that, we need to know the parts of a radical.

$\sqrt[n]{x}$ ,where n is the index and x is the radicand.

Radicals too, can be added together just like those regular numbers. It’s like adding a fraction, but first you need to make sure your index and your radicand are the same, just like how you need to have the same denominator when adding fractions.

E.g.

$2 \sqrt{4} + 2 \sqrt{4}$ $= 4\sqrt{2}$

in words, having 2 copies of

$\sqrt{25} + \sqrt{9}$

Don’t panic. See if they simplify to a whole number.

$\sqrt{25} + \sqrt{9}$ $= 5 + 3$ $= 8$

$\sqrt{27} - \sqrt{3}$ $= \sqrt{9 x 3} - \sqrt{3}$ $= 3\sqrt{3} - \sqrt{3}$ $= 2\sqrt{3}$