a) √3 x √15

b) √32 x √24

c) 2√5 x 5√2

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- Mar 12th 2010, 04:17 PMbrumby_3Simplify the following
a) √3 x √15

b) √32 x √24

c) 2√5 x 5√2 - Mar 12th 2010, 06:22 PMQuacky
Remember that $\displaystyle \sqrt{ab}=\sqrt{a}\times\sqrt{b}$

And that $\displaystyle \sqrt{x}\times\sqrt{x}=x$

1) $\displaystyle \sqrt{15}=\sqrt{3}\times\sqrt{5}$

so $\displaystyle \sqrt{15}\times\sqrt{3}$

$\displaystyle =\sqrt{3}\times\sqrt{3}\times\sqrt{5}$

How would this simplify?

2)$\displaystyle \sqrt{32}$

$\displaystyle =\sqrt{16}\times\sqrt{2}$

$\displaystyle =4\times\sqrt{2}$

And

$\displaystyle \sqrt{24}$

$\displaystyle =\sqrt{4}\times\sqrt{6}$

$\displaystyle =2\times\sqrt{6}$

Substitute these into the equation and then simplification should become clear.

3)Write this as:

$\displaystyle 2\times5\times\sqrt{2}\times\sqrt{5} $

Simplifying from here should be straightforward.

Reply if you are still stuck and I'll try to be of more assistance.