Chapter 9 - Quadratic Functions and Equations - 9-7 Linear Quadratic, and Exponential Models - Practice and Problem-Solving Exercises - Page 594: 33

$x=1.8$ or $x=-3.8$

We are given: $x^2+2x-7=0$ Use the quadratic formula. $x=\frac{-2+\sqrt 2^2-4.1.(-7)}{2.1}$ $x=\frac{-2 \pm 4\sqrt 2}{2}$ $x=\frac{-1\pm 2\sqrt 2}{1}$ $x=\frac{-1+2\sqrt 2}{1}$ or $x=\frac{-1-2\sqrt 2}{1}$ $x=1.8$ or $x=-3.8$