What is square root of 4x + 13 = 2x - 1

Hello:

√ (4x+13) = 2x-1 ... (1)

note : if (a=b) so (a² = b²)

if : (√ (4x+13)) ² = (2x-1) ² so : 4x+13 = 4x²-4x+1

4x²-8x-12 = 0

x²-2x-3 = 0

(x+1) (x-3) = 0

x+1 = 0 or x-3=0

x = - 1 or x=3

if : x = - 1 : √ (4 (-1) + 13) = 2 (-1) - 1

√9 = - 3 but √9 = 3

3 = - 3 impossible (-1 is not solution of equation (1)

if : x = 3 : √ (4 (3) + 13) = 2 (3) - 1

5 = 5 (right) conclusion : one solution : 3