1. **State the problem:** Given $ \frac{dy}{dx} = 7x^{2} - 5 $ and $ \frac{dx}{dz} = 6x - 4 $, find $ \frac{dy}{dz} $. 2. **Formula used:** By the chain rule for derivatives, we have $$\frac{dy}{dz} = \frac{dy}{dx} \times \frac{dx}{dz}$$ 3. **Substitute the given expressions:** $$\frac{dy}{dz} = (7x^{2} - 5)(6x - 4)$$ 4. **Expand the product:** $$\frac{dy}{dz} = 7x^{2} \times 6x - 7x^{2} \times 4 - 5 \times 6x + (-5) \times (-4)$$ $$= 42x^{3} - 28x^{2} - 30x + 20$$ 5. **Final answer:** $$\boxed{\frac{dy}{dz} = 42x^{3} - 28x^{2} - 30x + 20}$$