75= -5 ( -3-4x) First distribute by multiplying -5. 75= 15 + 20x by -3 and -5 by -4,
-15 -15 =
60=+20x
60=20x
60÷20=20÷20
3=x
then you try to isolate the variable, what that means is to try to get the variable, 20x, by itsself, you would do that by subtracting 15 from 15 and 75, you subtract 15 because it is positive, if it were negative then you would add it. You would then divide 20x and 60 by 20 to try to get rid of the 20, 60÷20=3, then you would bring the x down and, there it is, 3=x
I really hope that that helps and that I explained it well.
<<<sorry I didn't know that someone already answered it, I still hope it's helpful though.
