Always remember to use BEDMAS. Since we are following BEDMAS, we will be first solving the brackets:
7x - 4 - (x - 5) = 7x - 4 - x + 5
Now, since there's no exponents, division or multiplication, let's just simplify from left to right. (Remember that x says with other x values and cannot mix with numbers without x):
= 6x +1
Hope this helps!