Question 478235
{{{x^2+12x+36=64}}}...here you have a quadratic function and fist you need to write it in standard form {{{ax^2+bx+c=0}}}


{{{x^2+12x+36-64=0}}}


{{{x^2+12x-28=0}}}...now use a quadratic formula to find solutions

{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}...note that {{{a=1}}}, {{{b=12}}} and {{{c=-28}}}


{{{x = (-12 +- sqrt( 12^2-4*1*(-28) ))/(2*1) }}}

{{{x = (-12 +- sqrt(144+112))/2 }}}

{{{x = (-12 +- sqrt(256))/2 }}}

{{{x = (-12 +- 16)/2 }}}

solutions:

{{{x = (-12 + 16)/2 }}}

{{{x = 4/2 }}}

{{{x = 2 }}}

or

{{{x = (-12 - 16)/2 }}}

{{{x = -28/2 }}}

{{{x = -14 }}}

here is the graph:

{{{ graph( 500, 500, -20, 20, -50, 30,x^2+12x-28) }}}