For what values of r does the function y = e^rx satisfy the equation y'' + 4y' - 45y = 0?
Hello,
Why don't you just try to plug y = e^rx into the given equation and see what happens? You should notice that e^rx is never equal to zero, so this will lead you to a polinomial equation in r. Solve it and find the roots - they are what you're looking for.