Question 344965
Use the FOIL method,
{{{(5*sqrt(3)-15*sqrt(2))(4*sqrt(3)+12*sqrt(2))=20*3+60sqrt(6)-60sqrt(3)-180*2}}}
{{{(5*sqrt(3)-15*sqrt(2))(4*sqrt(3)+12*sqrt(2))=60-360}}}
{{{(5*sqrt(3)-15*sqrt(2))(4*sqrt(3)+12*sqrt(2))=highlight(-300)}}}