Chapter 7 Exponential and Logarithmic Functions - 7.3 Use Functions Involving e - 7.3 Exercises - Mixed Review - Page 498: 65

$$x=1+i\sqrt{\frac{7}{2}},\:x=1-i\sqrt{\frac{7}{2}}$$

Using the quadratic formula, we find: $$x_{1,\:2}=\frac{-\left(-4\right)\pm \sqrt{\left(-4\right)^2-4\cdot \:2\cdot \:9}}{2\cdot \:2} \\ x=1+i\sqrt{\frac{7}{2}},\:x=1-i\sqrt{\frac{7}{2}}$$