Question 54218
You can only combine square roots if the insides equal.  Divide the insides as factors involving perfect squares:
{{{5*sqrt(8)+sqrt(98)-2*sqrt(18)}}}
{{{5*sqrt(4)*sqrt(2)+sqrt(49)*sqrt(2)-2*sqrt(9)*sqrt(2)}}}
{{{5*2*sqrt(2)+7*sqrt(2)-2*3*sqrt(2)}}}
{{{10*sqrt(2)+7*sqrt(2)-6*sqrt(2)}}}
{{{(10+7-6)*sqrt(2)}}}
{{{highlight(11*sqrt(2))}}}
Happy Calculating!!!