So to solve your question, we can use this:
[tex]\sf{a(b-c) = ab-ac}[/tex]
[tex]\sf{a(b+c) = ab+ac}[/tex]
So then
[tex]\sf{-(6w-1)}[/tex]
If we use the above formulas then:
[tex]\sf{-(6w-1) = -6w+1}[/tex]
And for
[tex]\sf{3(w-4)}[/tex]
We will get:
[tex]\sf{3(w-4) = 3w-3(4) =3w-12}[/tex]
And to simplify
[tex]\sf{-(6w-1)+3(w-4)}[/tex]
Since we already calculated the individual parts, not put them together, so:
[tex]\sf{-6w+1+3w-12}[/tex]
Now we have to add the like terms which are -6w and 3w. And also 1 and -12.
Rearranging the terms, we get:
[tex]\sf{-6w+3w-12+1}[/tex]
And [tex]\sf{-12+1=-11}[/tex]
And also [tex]\sf{-6w+3w= w(-6+3) = w(-3) = -3w}[/tex]
So combining that, we get:
[tex]\sf{-3w-11}[/tex]
Which is your final answer :)