Đáp án + Giải thích các bước giải:
`A = (1/(3-sqrt5)-1/(3+sqrt5)) : (sqrt5-5)/(1-sqrt5)`
`= (3+sqrt5-(3-sqrt5))/((3-sqrt5)(3+sqrt5)) * (1-sqrt5)/(sqrt5-5)`
`= (3+sqrt5-3+sqrt5)/((3-sqrt5)(3+sqrt5)) * (1-sqrt5)/(sqrt5-5)`
`= (2sqrt5(1-sqrt5))/((3-sqrt5)(3+sqrt5)(sqrt5-5))`
`= (2sqrt5-10)/((3^2-sqrt5^2)(sqrt5-5))`
`= (2(sqrt5-5))/(4(sqrt5-5))`
`= 1/2`
`B = 6sqrt3 + sqrt{(1-sqrt3)^2} - 4/(sqrt3+1)`
`= 6sqrt3 + |1-sqrt3| - (4(sqrt3-1))/((sqrt3+1)(sqrt3-1))`
`= 6sqrt3 + sqrt3 - 1 - (4(sqrt3-1))/(sqrt3^2-1^2)` (Do `1- sqrt3 < 0`)
`= 6sqrt3 + sqrt3 - 1 - 2(sqrt3-1)`
`= 6sqrt3 + sqrt3 - 1 - 2sqrt3 + 2`
`= 5sqrt3 + 1`
