ANSWER
[tex]x = - 10[/tex]
EXPLANATION
We have the quadratic equation
[tex](x + 10)(x + 10) = 0[/tex]
This quadratic equation is in the factored form.
According to the zero product principle either the first factor is zero or the second is zero.
We apply the zero product principle to obtain:
[tex](x + 10) = 0 \: \: or \: \: (x + 10) = 0[/tex]
This is a repeated factor therefore,
[tex]x = - 10[/tex]
is the repeated root.
