I think you left off the 2 coefficient and also you left
the square root symbol off of the 7 in what you
multiplied by.
To find out what to multiply by,
take the denominator,
Change the sign of the SECOND term, so that
you have
Now put that over itself:
so that it will just equal to 1 and therefore
it won't affect the value of the original
problem when we multiply by it.


Put parentheses around all numerators and denominators:


Indicate the multiplication of the numerators and
denominators, so that we just have one fraction:
FOIL out the top and bottom:
The middle two tems in the bottom cancel out:
Take square roots of 9 and 49, which are 3 and 7:
Edwin