Question 65685
Simplify by co,bining like terms:

sqrt 63  - 2sqrt28  + 5sqrt7

Separate factors that are perfect squares: 1,4,9,16,25,...=1^2, 2^2, 3^2, 4^2, 5^2,...
{{{sqrt(9)*sqrt(7)-2*sqrt(4)*sqrt(7)+5*sqrt(7)}}}
{{{3*sqrt(7)-2*2*sqrt(7)+5*sqrt(7)}}}
{{{3*sqrt(7)-4*sqrt(7)+5*sqrt(7)}}}
{{{(3-4+5)*sqrt(7)}}}
{{{highlight(4*sqrt(7))}}}
Happy Calculating!!!