Question 422153
{{{(3-2sqrt(7))(3+2sqrt(7))}}}
You could use FOIL to multiply these.<br>
But your expression fits the {{{(a-b)(a+b) = a^2-b^2}}} pattern so we can use the pattern to multiply, too. I like using the patterns. So
{{{(3-2sqrt(7))(3+2sqrt(7)) = (3)^2 -(2sqrt(7))^2 = 9 - 4*7 = 9 - 28 = -19}}}
which is the same answer you would get from FOIL (if you do it correctly).