-(1+7x)-6(-7-x)=36

-(1+7x)-6(-7-x)=36

(-1)(1) (-1)(+7x)-6(-7-x)=36

-1-7x-6(-7-x)=36

-1-7x (-6)(-7) (-6)(-x)=36

-1-7x+42+6x=36

-1x+41=36

-1x+41-41=36-41

-1x=-5

-1x/-1=-5/-1

x=5