Question 86828
square root 63- 2(square root 28) + 5 (square root 7) 
:
{{{sqrt(63) - 2sqrt(28) + 5sqrt(7)}}}
:
Find the perfect squares inside the radicals:
{{{sqrt(9*7) - 2sqrt(4*7) + 5sqrt(7)}}}
:
Extract roots of the squares:
{{{3sqrt(7) - 2*2sqrt(7) + 5sqrt(7)}}}
:
{{{3sqrt(7) - 4sqrt(7) + 5sqrt(7)}}}
:
Like terms, just do the math:
{{{+4sqrt(7)}}}