2x-(-1/2x-1/2)=8
the - sign before the first parentheses is a negative 1
you distribute the -1 into the parentheses
-1 multiplied by -1/2x is 1/2x and -1 multiplied by -1/2 is 1/2.
so now we have 2x-1/2x+1/2=8
you combine like terms (2x and -1/2x)
you get 1 1/2x+1/2=8
you subtract the 1/2 to get 1 1/2x= 7 1/2
you divide everything by 1 1/2.
the answer is x=5