Respuesta :

ab = (7x-6) →   b = (7x-6)/a   (1)

bc = (12-2x) → b = (12-2x)/c   (2)

Since (1) = (2) → (7x-6)/a = (12-2x)/c OR  a/c = (7x-6)/(12-2x)  (3)

Multiply  both numerators of (3) by the SQUARE of their  respective denominators;

(a*c²)/c = (7x-6)(12-2x)²/(12-2x)
Now simplify:

ac = (7x-6)(12x-2x)  or ac = -14x² + 96x - 72