Question 1059706
Try it this way:


{{{2a^2+4a=-5}}}

{{{2(a^2+2a)=-5}}}

and then INSIDE the parentheses, add the term  {{{(2/2)^2=1}}}, but on the right-hand member, you must account for the factor in the left-side member which has been factorized....


{{{2(a^2+2a+1)=-5+2*1}}}

{{{2(a^2+2a+1)=-5+2}}}


If that is clear for you, then continue.