Solve each system by substitution method 1) y=x^2+6x+9 2) x+y=3

y=3-x 
y=x^2+6x+9 

leads to

3-x=x^2+6x+9 

x^2+7x+6=0 
(x+6)(x+1)=0 

x=-1 or x=-6


:)