What ia the common ratio of the sequence? -2 , 6, -18,

Its a multiplication by -3 on each term, so I think you're gonna answer is by r=-3, maybe?

(m+11n)^2=(m+11n)(m+11n)=m^2+11mn+11mn+121n^2=m^2+22mn×121n^2 for example; use foil: (a+b)(a+b)first. a^2outside. abinside. ablast. b^2