Help me please :( help

What term best describes a line ans a point that lie in the same plane

On a piece of paper graph f(x)=5•(0.4)^x

Determine the fraction of total interest owed. after the fourth month of a 12-month loan: the numerator is: {(n + ) + (n + ) + (n + ) + (n + )} = , and the denominator is: {(n) + (n + 1) + + (n + )} = . therefore, the fraction is numerator/denominator (to the nearest tenth) =