Because your question isn't specific or formatted exactly, I cannot guarantee that my answer is what you expect.
√2x - 1 + 2 = 5
√(2x + 1)² = 5²
2x + 1 = 25
2x = 24
/2 /2
x = 12
Therefore x = 12.
Proof:
√2x - 1 + 2 = 5
√2(12) - 1 + 2 = 5
√24 - 1 + 2 = 5
√25 = 5
5 = 5