Question

find all numbers for which the rational expression is undefined
(m^3-6m)/(m^2-81)

Answer 1

- firstly when (m*2 -81) will be zero that so m=+/- 9
- second when m*3-6m=0 --- m(m*2-6)=0 --- m=0
m*2-6=0 --- m*2=6 --- m=+/- radical 6