Question 523319
  {{{(x^2+8x+16) = 9}}}  Here you have to apply {{{(a+b)^2 = a^2 + 2ab + b^2}}}

  {{{x^2+2*4*x+4^2 = 9}}}  =  {{{(x+4)^2 = 9}}} Now taking out the square root both the sides we get,
  {{{x+4 = 3}}}  Now subtracting 4 from both the sides, we get

  {{{x+4-4 = 3-4}}};  So, x = -1.