Chapter 4 Quadratic Functions and Factoring - 4.8 Use the Quadratic Formula and the Discriminant - 4.8 Exercises - Skill Practice - Page 296: 28

$$x=\frac{1}{15},\:x=-\frac{4}{3}$$

Solving the equation using the quadratic formula, we find: $$x_{1,\:2}=\frac{-57\pm \sqrt{57^2-4\cdot \:45\left(-4\right)}}{2\cdot \:45} \\ x=\frac{1}{15},\:x=-\frac{4}{3}$$ Checking by factoring the expression, we find: $$3x\left(15x-1\right)+4\left(15x-1\right) \\ \left(15x-1\right)\left(3x+4\right)$$