Answer:
m = 0
m = 7
m = -4
Step-by-step explanation:
[tex]\sf 9m^3-27m^2-252m=0[/tex]
Divide by 9:
[tex]\sf \implies m^3-3m^2-28m=0[/tex]
Factor out common term m:
[tex]\sf \implies m(m^2-3m-28)=0[/tex]
Factor expression in parentheses:
[tex]\sf \implies m(m-7)(m+4)=0[/tex]
Therefore,
[tex]\sf \implies m=0[/tex]
[tex]\sf \implies m-7=0 \implies m=7[/tex]
[tex]\sf \implies m+4=0 \implies m=-4[/tex]