Answer: [tex]21m^7-7m^5+49=7m(3m^6-m^4+7)[/tex]
Explanation: Given expression [tex]21m^7-7m^5+49m[/tex]
We can write , [tex]21m^7-7m^5+49= 7m\times3m^6- 7m\times m^4+7m\times7[/tex]
Since, in the right side of the above expression 7m is common in every term. so, we can take it common with help of bracket.
Therefore, [tex]21m^7-7m^5+49= 7m(3m^6-m^4+7)[/tex]