solution:
[tex]x^2+6x=16\\
x^2+6x-16=0\\
solving for variable'x'\\
add 16 to each side of the equation\\
x^2+6x+16-16=0+16\\
x^2+6x=16\\
the x term is 6x.take half its cofficient(3),square it (9)and it to both side\\
add 9 to each side of the equation\\
6x+9+x^2=16+9\\
x^2+6x+9=25\\[/tex][tex]factor a ferfect square of the right side 5\\
this problem into teo subproblem by (x+3) equal to 5 and -5\\
sub problem 1\\
x+3=5\\
x=5-3\\
x=2\\
sub problem 2\\
x+3=-5\\
x=-5-3\\
x=-8\\
the solution to the problem is based on the solution from the sub problem is\\
x={2,-8}[/tex]