Question 1058454
<pre>
Looks like you made a sign error, 3+4 should have been 3-4.
Multiply the bottoms using FOIL

{{{sqrt(7)/(sqrt(3)+2)}}}

{{{(sqrt(7)/(sqrt(3)+2))*((sqrt(3)-2)/(sqrt(3)-2))}}}

{{{(sqrt(7)*(sqrt(3)-2))/((sqrt(3)+2)(sqrt(3)-2))}}}

Use FOIL in the denominator:

{{{(sqrt(7)sqrt(3)-2sqrt(7))/((sqrt(3)^2-2sqrt(3)+2sqrt(3)-2^2))}}}

[That was where you made your error]

{{{(sqrt(21)-2sqrt(7))/(3-2sqrt(3)+2sqrt(3)-4))}}}

{{{(sqrt(21)-2sqrt(7))/(3-cross(2sqrt(3))+cross(2sqrt(3))-4))}}}

{{{(sqrt(21)-2sqrt(7))/(3-4))}}}

{{{(sqrt(21)-2sqrt(7))/(-1)}}}

{{{(sqrt(21)-2sqrt(7))/(-1)}}}{{{""*""}}}{{{(-1)/(-1)}}}

{{{(-sqrt(21)+2sqrt(7))/1}}}

{{{2sqrt(7)-sqrt(21)}}}

Yes the book is wrong!

Edwin</pre>