1. The problem is to simplify the expression $-\left|-x\right|$. 2. Recall that the absolute value function $|a|$ returns the non-negative value of $a$, so $|-x| = |x|$ because absolute value removes the negative sign. 3. Substitute $|-x|$ with $|x|$ in the expression: $$-\left|-x\right| = -|x|$$ 4. The expression $-|x|$ means the negative of the absolute value of $x$, which is always less than or equal to zero. 5. Therefore, $-\left|-x\right|$ does not simplify to $x$, it simplifies to $-|x|$. 6. In summary, $$-\left|-x\right| = -|x|$$ and this is not equal to $x$ unless $x=0$.