Answer
for the elephant: $|x-6008|\leq5992$
for the mouse: $|x-46000|\leq45000$
Work Step by Step
If $a\leq x\leq b$, we can turn this into an absolute value inequality in the following way:
Take the mean of $a$ and $b$: $\frac{a+b}{2}$. This will be equidistant from $a$ and $b$. Thus if we take x's difference from this, it must be within $|a-\frac{a+b}{2}|=|b-\frac{a+b}{2}|$. Thus the inequality will be: $|x-\frac{a+b}{2}|\leq|a-\frac{a+b}{2}|$.
Hence here the inequalities are:
for the elephant: $|x-\frac{16+12000}{2}|\leq|16-\frac{16+12000}{2}|\\|x-6008|\leq5992$
for the mouse: $|x-\frac{1000+91000}{2}|\leq|1000-\frac{1000+91000}{2}|\\|x-46000|\leq45000$
