Calculate: (5)/(7)m-2-(6)/(7)m=-13

Expression: $\frac{ 5 }{ 7 }m-2-\frac{ 6 }{ 7 }m=-13$

Multiply both sides of the equation by $7$

$5m-14-6m=-91$

Collect like terms

$-m-14=-91$

Move the constant to the right-hand side and change its sign

$-m=-91+14$

Calculate the sum

$-m=-77$

Change the signs on both sides of the equation

$m=77$