Consider the given that 6x3−5x2−13x+12
Put x=1 and we get,
6(1)3−5(1)2−13(1)+12
=6−5−13+12=0
Then, x=1 and x−1=0 is a factor.
Now figure above
6x3−5x2−13x+12=(x−1)(6x2+x−12)=0
⇒(x−1)(6x2+x−12)=0
⇒(x−1)(6x2+(9−8)x−12)=0
⇒(x−1)(6x2+9x−8x−12)=0
⇒(x−1)[3x(2x+3)−4(2x+3)]=0
⇒(x−1)(3x−4)(2x+3)=0
If x−1=0 then x=1
If 3x−4=0 then x=43
If 2x+3=0 then x=−32
Hence, the factor is 1,−32 and 43.