Simplify :
` ( 1 - sqrt(-1 )) ( 1 + sqrt(-1 )) ( 5 - sqrt(-7 )) ( 5 + sqrt(-7))`

simplify (5+sqrt(7))(5+sqrt(2))

(5-sqrt(-7))(5+sqrt(-7))(2-sqrt(-1))(2+sqrt(-1))

(sqrt(7)+1)/(sqrt(7)-1)-(sqrt(7)-1)/(sqrt(7)+1)=a+b sqrt(7)

Simplify. (4)/(7)sqrt(147)+(3)/(8)sqrt(192)-(1)/(5)sqrt(75)

The value of (1)/( sqrt(7) - sqrt(6)) - (1)/( sqrt(6) - sqrt(5) ) +(1)/( sqrt(5) -2) - (1)/( sqrt(8) - sqrt(7) ) +(1)/( 3- sqrt(8)) is

Simplify: (7+3sqrt(5))/(3+sqrt(5))-(7-3sqrt(5))/(3-sqrt(5)) (ii) (1)/(2+sqrt(3))+(2)/(sqrt(5)-sqrt(3))+(1)/(2-sqrt(5))