Chapter 11 - Quadratic Functions and Equations - 11.3 Studying Solutions of Quadratic Equations - 11.3 Exercise Set - Page 718: 40

$$x^2-0.8x-0.84=0$$

To write a quadratic equation with the given values as solutions, we find the corresponding factors. We then FOIL out the factors to find the original quadratic equation: $$ 0=\left(x+0.6\right)\left(x-1.4\right) \\ 0= xx+x\left(-1.4\right)+0.6x+0.6\left(-1.4\right) \\ 0= x^2-0.8x-0.84$$