Solve s=w- 10e / m. For w
W=MS/-10E
Because if you multiply each side by M/-10E you'll isolate W
The way you wrote the problem was kind of confusing, so I'm not sure which one of these you meant.
\(s= \frac{w-10e}{m} \\
sm = w-10e\\
sm + 10e = w\)
\(s=w- \frac{10e}{m}\\
s+ \frac{10e}{m} =w\)