Chapter 9 - Trigonometric Identities, Models, and Complex Numbers - 9.2 Identities, Expressions, and Equations - Exercises and Problems for Section 9.2 - Exercises and Problems - Page 363: 10

$$6\cos \left(t\right)-14 sint$$

Simplifying the expression, we obtain: $$2\cos \left(t\right)\left(3-7\tan \left(t\right)\right)$$ Since tangent equals $\frac{sint}{cost}$, it follows: $$6\cos \left(t\right)-14\cos \left(t\right)\tan \left(t\right) \\ 6\cos \left(t\right)-14 sint$$