I have no idea what this question means but if anyone understands it or has an answer much help is apreciated! :)

Here, we have to factorise :
Consider the largest number which is the factor of both -12 and -20, that is -4.
→ -4 × 3n = -12n
→ -4 × 5 = -20
Taking (-4) as common,
→ -4( 3n + 5 )