We need to FOIL that out and then get it into standard form to see what our A, B, and C are. FOILing gives us [tex]25-x^2=7[/tex]. If we move the 7 over by subtraction and set it equal to 0, we have [tex]-x^2+18=y[/tex]. In order to avoid a negative leading coefficient, we can change all the signs to get [tex]x^2-0x-18=0[/tex] so A = 1, B = 0, C = -18, first choice above.