7a-3(2a-4) what’s the answer?

What’s the numerical coefficient of 6xy

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.

Find the solution of system of equation y= x-4 y=4x+2