### Home > A2C > Chapter Ch9 > Lesson 9.3.3 > Problem 9-171

9-171.

Treat this as a difference of squares.

Use the Quadratic Formula, then use those answers as factors.

Using complex numbers, this can be treated as a difference of squares.

*x*^{2} + 4 = *x*^{2} − (−4)

(*x* + 2*i*)(*x* − 2*i*)

See part (b).