Hello quah13579(a) means that the numerical value of is less than . So lies between and .

Take the LH inequality:

...and the RH inequality:

So, combining these two answers into one:

(b) Although you had a LaTeX error in your original posting, I assume it's

So

When we take square roots, be careful with the negative values. We need to use an absolute value sign |...|, like this:

or

Grandad