>>7613284Why are you figuring out the coefficient of friction, you are making extra work for yourself. They give you the final force it generates, which is -950 if you say the other force is in the positive direction. so the final equation is mv^2/(1140-950) = d.
But more specifically for your question. You can't remove something for the denominator if it isn't outside of the brackets of the addition or subtraction part. If that explanation doesn't make sense I can post a picture explaining it better.
