A) t = sqrt((2x+3)/(2x-1))
t + 4/t = 4
t^2 - 4t +4 = 0
t = 2
sqrt((2x+3)/(2x-1)) = 2
(2x+3)/(2x-1) = 4
2x+3 = 8x-4
x = 7/6
б) t = sqrt((5x-1)/(x+3))
t^2 - 6t + 5 = 0
t1 = 1; t2 = 5 - не удовл.
sqrt((5x-1)/(x+3)) = 1
(5x-1)/(x+3) = 1
5x - 1 = x +3
4x = 4
x = 1