x-2 = sqrt(x) /**/ <=> x^2 - 4x + 4 = x /\ x >= 2 /**/ <=> x^2 - 5x + 4 = 0 /\ x >= 2 /**/ <=> (x = (5 + sqrt(9))/2 \/ x = (5 - sqrt(9))/2) /\ x >= 2 /**/ <=> (x = 4 \/ x = 1) /\ x >= 2 /**/ <=> x = 4