View Full Version : Practice exam for compass test
adkloup
Jun 9, 2009, 07:48 AM
for all x>0 and y>0, the radical expression
√x
3√x - √y
is equivalent to :
3x - √y
9x + y
3x - √xy
3x + y
3x + √xy
9x - y
3x + √xy
3x - y
x
3x - y
those are spost to be fractions didn't know how to do that
Perito
Jun 9, 2009, 08:44 AM
for all x>0 and y>0, the radical expression
√x
3√x - √y
is equivalent to :
3x - √y
9x + y
3x - √xy
3x + y
3x + √xy
9x - y
3x + √xy
3x - y
x
3x - y
those are supposed to be fractions didn't know how to do that
\Large \frac {\sqrt{x}}{3\sqrt{x} - sqrt{y}}
Multiply top and bottom by \Large 3\sqrt{x}+sqrt{y}. The reason I picked that is a^2-b^2=(a-b)(a+b). I'm trying to get roots out of the denominator.
\Large \left( \frac {\sqrt{x}}{3\sqrt{x} - sqrt{y}} \right) \left(\frac {3\sqrt{x}+\sqrt{y}}{3\sqrt{x}+\sqrt{y}}\right) = \frac {3x+\sqrt {xy}}{9x-y}
I think this is one of your choices.