-2m - 33 = 3(1 - 8m) + 4m

M=2

Remove the parenthesis and distribute 3 through the parenthesis so it’ll be -2m-33=3-24m+4m
Collect like terms so -24m+2m will become -2m-33=3-20m
Move the two variables on left hand side so it’ll be -2m+20m=3+33 (it’s more easier for me to do that)
Then collect like terms for the m -2m-20m =
18m=3+33
Add the 3 and 33
Divide both sides by 18 to get 2
Hope this helps