to solve it, remember that
for [tex]a^2=b[/tex], assume a=b and a=-b
also, [tex]i^2=-2[/tex]
so
[tex](x+9)^2=-64[/tex]
64 is a perfect square but -64 isn't
hmm, we can factor out the -1
[tex](x+9)^2=(-1)(64)[/tex[
[tex]-1=i^2[/tex]
[tex](x+9)^2=(i^2)(8^2)[/tex]
[tex](x+9)^2=(8i)^2[/tex]
square root both sides
x+9=8i or -8i
minus 9 from both sides
x=8i-9 or -8i-9
