CPM Homework Help : CALC Problem 7-121

Which of the following differential equations could model a population whose rate of change is proportional to the existing population? Explain your reasoning. Is it possible that there is more than one answer?

$\frac { d P } { d t }= 3P$

$\frac { d P } { d t }= 3t$

$\frac { d P } { d t }= −3P$

$\frac { d P } { d t }= 3$

Hint:

A proportional situation follows the patten: $y = kx$ .