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Simplify the following expressions:(i) (4 + \(\sqrt7\)) (3 + \(\sqrt2\))(ii) (3 + \(\sqrt3\)) (5 - \(\sqrt2\))(iii) (\(\sqrt5\) - 2)(\(\sqrt3\) - \(\sqrt5\)) |
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Answer» (i) (4 + \(\sqrt7\))(3 + \(\sqrt2\)) = 4 x 3 + 4 x \(\sqrt2\) + \(\sqrt7\) x 3 + \(\sqrt7\) x \(\sqrt2\) = 12 + 4\(\sqrt2\) + 3\(\sqrt7\) + \(\sqrt14\) (ii) (3 + \(\sqrt3\))(5 - \(\sqrt2\)) = 3 x 5 + 3 x (-\(\sqrt2\)) + \(\sqrt3\) x 5 + \(\sqrt3\) x (-\(\sqrt2\)) = 15 - 3\(\sqrt2\) + 5\(\sqrt3\) - \(\sqrt3\) x 2 = 15 - 3\(\sqrt2\) + 5\(\sqrt3\) - \(\sqrt6\) (iii) (\(\sqrt5\) - 2)(\(\sqrt3\) - \(\sqrt5\)) = \(\sqrt5\) x \(\sqrt3\) + \(\sqrt5\) x (-\(\sqrt5\)) + (-2) x \(\sqrt3\) +(-2) x (-\(\sqrt5\)) = \(\sqrt5\) x 3 - \(\sqrt5\) x 5 - 2\(\sqrt3\) + 2\(\sqrt5\) = \(\sqrt15\) - \(\sqrt{5^2}\) - 2\(\sqrt3\) + 2\(\sqrt5\) = \(\sqrt15\) - 5 - 2\(\sqrt3\) + 2\(\sqrt5\) |
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