178.
If number CLXXVIII is within to text or sentence it should be read in its equivalent in arabic numbers, in this case 178.
:)
well, you already know an absolute value expression has a ± siblings, so let's proceed without much fuss.
![\bf |2x-5|=4\implies \begin{cases} +(2x-5)=4\implies 2x=9\implies x=\cfrac{9}{2}\\[-0.5em] \hrulefill\\ -(2x-5)=4\implies 2x-5=-4\\[1em] 2x=1\implies x=\cfrac{1}{2} \end{cases}](https://tex.z-dn.net/?f=%20%5Cbf%20%7C2x-5%7C%3D4%5Cimplies%20%20%5Cbegin%7Bcases%7D%20%2B%282x-5%29%3D4%5Cimplies%202x%3D9%5Cimplies%20x%3D%5Ccfrac%7B9%7D%7B2%7D%5C%5C%5B-0.5em%5D%20%5Chrulefill%5C%5C%20-%282x-5%29%3D4%5Cimplies%202x-5%3D-4%5C%5C%5B1em%5D%202x%3D1%5Cimplies%20x%3D%5Ccfrac%7B1%7D%7B2%7D%20%5Cend%7Bcases%7D%20)
If you have questions, feel free to ask
13. Is 18
15. Is 86
17 is 5
19 is 15
21 is 24
23 is 29