Question

Show that x=-3 is a solution of x^2 + 6x +9=0

Answer 1

put x= -3 in the equation
LHS=RHS=0
therefore x=-3 is a solution of the given equation

Answer 2

$put \: x = - 3 \\ {x}^{2} + 6x + 9 \\ = {( - 3)}^{2} + 6( - 3) + 9 \\ = 9 - 18 + 9 \\ = 0 \\ so \: x = - 3 \: is \: a \: solution \:$