the square root of 6 can be written as sqrt6.
7 multiplied by the square root of 3 can be written as 7sqrt3.
6 added to 7 multiplied by the square root of 3 can be written as 7sqrt3 + 6
therefore the square root of 6 * (7 multiplied by the square root of 3) + 6) is written as sqrt6(7sqrt3+6).
to solve sqrt6(7sqrt3+6), multiply the two terms in the bracket separately with the term outside the bracket.
sqrt6 * 7sqrt3 = 7 * (sqrt6 * sqrt3) = 7 sqrt18
sqrt18 = sqrt9 * sqrt2 = 3 * sqrt2
7 * sqrt18 = 7 * 3 * sqrt2 = 21 * sqrt2
sqrt6 * 7sqrt3 = 21sqrt2
sqrt6 * 6 = 6sqrt6
sqrt6(7sqrt3+6) = (sqrt6 * 7sqrt3) + (sqrt6 * 6)
= 21sqrt2 + 6sqrt6
the roots cannot be simplified further, but you may wish to factorise:
21sqrt2 = 3 * 7sqrt2
6sqrt6 = 3 * 2sqrt6
21sqrt2 + 6sqrt6 = 3(7sqrt2 + 2sqrt6)