Factorise x^2+6x+8=0 to get (x+4)(x+2)=0
Solve to get x=-4, x=-2
Factorise x^2+6x+13=0 (I assumed you mistyped and wrote * instead of +)
Use the quadratic formula and you find that there are no real roots so the answer for this is just x=-4, x=-2
Tell me if I made any mistakes