help

it's a minus sign, it means subtraction

\(4x - (x+8) = \\ 4x - x - 8 = \\ 3x-8\)

4x- (x+8) 

there are many ways that you can think of this but the answer will always be the same.

Consider 

10 - (3+5)

the answer is 10-8 = 2

which is the same as   10 - 3 - 5 = 2

so

4x - (8+x) = 4x - 8 -x     =  3x-8

OR

If there is a minus sign in front of a bracket you can get rid of the bracket and the minus sign by changing the sign of everything within th bracket. Minus signs become + and plus becomes -

4x - (8+x)

=4x - (+8+x)

=4x    -8-x

=3x-8

OR

Another way I like to look at it is that you are adding -1 times the bracket

so

4x - (x+8)

=4x+     (-1)(x+8)

=4x+        -1*x + -1*8

=4x+           -x   -   8

=3x - 8