Answer:
[tex]49m^2n^2 + 14mn + 1[/tex]
Step-by-step explanation:
this is equivalent [tex](7mn+1)(7mn+1)<->(7mn+1)^2[/tex]
identity of squaring this kind of equation is:
[tex](a+b)^2 = a^2 + 2ab + b^2[/tex]
here, a = 7mn and b = 1
so, this expands to [tex]49m^2n^2 + 14mn + 1[/tex]