Using substitution, I merged the two equations setting them equal to each other:
[tex] 3 = -x^{2} + 6x - 8 [/tex]
Then, in order to make one side zero, all you have to do is subtract 3 from each side.
Your answer would be:
[tex] 0 = -x^{2} + 6x - 8 [/tex]
