M=\(\frac{2a+b}{a-b}-\frac{2a-b}{a+2b}\)
M=\(\frac{2a+6b-5b}{a+3b-4b}-\frac{2a+6b-7b}{a+3b-1b}\)
M=\(\frac{2\left(a+3b\right)-5b}{\left(a+3b\right)-4b}-\frac{2\left(a+3b\right)-7b}{\left(a+3b\right)-1b}\)
M=\(\frac{-5b}{-4b}-\frac{-7b}{-1b}\)
M=\(\frac{5}{4}-\frac{7}{1}\)
M=\(-5\frac{3}{4}\)