5x+7+3x=-8+3x please solve it before 8:30

The physical fitness of an athlete is often measured by how much oxygen the athlete takes in (which is recorded in milliliters per kilogram, ml/kg). the mean maximum oxygen uptake for elite athletes has been found to be 60 with a standard deviation of 7.2. assume that the distribution is approximately normal.

Using the side-splitter theorem, daniel wrote a proportion for the segment formed by luke segment de. what is ec?

If you could answer these your a life saver