Classify the system of equations. -x=1-y -1+y=x+2. coincident, intersecting, parallel

Solve for n? [tex]z = \frac{3}{4} mn[/tex]

Find the distance between (0,5) & (-4,2)

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?