We must have `x-2 ge 0` for `sqrt(x-2)` to get defined , thus `x ge 2`. Now `sqrt(x-2 )ge -1` as square roots are always non-negative . Hence , `x ge 2` Note : Some students solve it by squaring on both sides for which `x-2 gt -1 " or " x ge 3 ,` which causes loss of interval [ 2,3}`