`a, x + 5 - sqrt x = 1`
`<=> x - sqrt x + 4 = 0`
`<=> x - sqrt x + 1/4 + 15/4 =0`
`<=> (sqrt x+1/2)^2 + 15/4 = 0`
`=> x = cancel o`.
`b, sqrt(2x-5) - sqrt(18x-45) = -3`
`<=> sqrt(2x-5) - 3(sqrt(2x-5)) = -3`
`=> -2sqrt(2x-5) = -3`
`=> sqrt(2x-5) = 3/2`
`=> 2x - 5 = 9/4`
`=> 2x = 7,25`
`=> x = 3,625`