Chapter 5 - Polynomials and Polynomial Functions - 5-5 Theorems About Roots of Polynomial Equations - Practice and Problem-Solving Exercises - Page 317: 53

$y = \dfrac{1}{6}$

We will use elimination to find the value of $y$. We multiply the first equation by $-4$ tand multiply $5$ to the second equation to obtain the equivalent system: $-40x - 96y = -36$ $ 40x + 300y = 70$ Add the equations together to obtain $204y = 34$ Divide each side by $204$ to get: $y = \dfrac{34}{204}$ $y = \dfrac{1}{6}$