# How do you find the complex roots of #6c^3-3c^2-45c=0#?

##### 1 Answer

Nov 27, 2016

Remove a common factor of

#6c^3-3c^2-45c=0#

#3c(2c^2-c-9)=0#

Checking the discriminant of the resulting quadratic,

The first zero comes from

The second two, through the quadratic formula for

#c=(1+-sqrt(1-4(2)(-9)))/4=(1+-sqrt73)/4#

We see that our three zeros are