Observed elevation differences and line lengths of a level network are shown below:

$\backslash$table$[[$Line$,$Height difference $(m),$Distance $(km)$ please answer all and show all workings. i will appreciate. Adjust the level net of the figure above by weighted least squares, and compute precisions of the adjusted benchmarks. In the figure, the benchmark elevations $($in meters$)$ and course lengths $($in kilometers$)$ are shown in parentheses. Observed elevation differences for courses $1$ through $5($given in order$)8\mathrm{.}847$m$,-11\mathrm{.}319$m$,+1\mathrm{.}382$m$,+2\mathrm{.}708$m and $-4\mathrm{.}352$m$.$ Arrows on the courses in the figure indicate the direction of leveling. Thus, for course $1$ having a length of $2$km$,$ leveling proceeded from BM $1$ to A and the observed elevation difference was $10\mathrm{.}970$m$.($Assume that weights are inversely proportional to course lengths$).$