9m^2-(1+2m)^2 разложите ** множители

Question

9m^2-(1+2m)^2 разложите на множители

Answer 1

9m²-(1+2m)²=(3m-(1+2m))(3m+1+2m)=(3m-1-2m)(5m+1)=(m-1)(5m+1).

Answer 2

=9m²-1-4m-4m²=5m²-4m-1=(m-1)(m+0.2)
 5m²-4m-1=0
  D=16-4*5*(-1)=36=6²
   m=(4+6)/10=1