maths question

1. x + 1/x = 29/10
10x^2 - 29x + 10 = 0
(5x - 2)(2x - 5) = 0
x = 2/5　or　x = 5/2
2. √( x + (3√x + 1) ) = 3
x + 3√(x + 1) = 9
9x + 9 = 81 - 18x + x^2
x^2 - 27x + 72 = 0
(x - 3)(x - 24) = 0
x = 3　or　x = 24 (rejected)
3. √(3x+10) - √(x-4) = √(2x+6)
3x + 10 - 2√(3x + 10)(x - 4) + x - 4 = 2x + 6
2x = 2√(3x^2 - 2x - 40)
x^2 = 3x^2 - 2x - 40
x^2 - x - 20 = 0
(x - 5)(x + 4) = 0
x = 5　or　x = -4 (rejected)

1.x+1/x=29/10
x^2+1=29/10x
10x^2+10=29x
10x^2-29x+10=0
(5x-2)(2x-5)=0
x=2/5 or x=5/2