$-13 = 5(1 + 4m)-2m$

Explanation:

Step1: Expand the right - hand side

$-13 = 5\times1+5\times4m - 2m$ $-13 = 5 + 20m-2m$

Step2: Combine like terms

$-13 = 5+(20m - 2m)$ $-13 = 5 + 18m$

Step3: Isolate the term with m

Subtract 5 from both sides: $-13-5=18m$ $-18 = 18m$

Step4: Solve for m

Divide both sides by 18: $m=\frac{-18}{18}$ $m=-1$

Answer:

$m = - 1$