What is 4x - (9-3x) = 8x-1

First you have to distribute the negative (=-1) with the numbers in the parentheses.

-1*9=-:

-1*-3x=3x

You now have:

4x-9+3x=8x-1

Now combine like terms:

4x+3x=7x

Now you have:

7x-9=8x-1

Now isolate that x:

7x-8x=-x

-1+9=8

You now have:

-x=8

Divide by - 1 and get:

x=-8