And look for the common denominator of the entire equation, and that's going to be Z. So we know that Z can never equal 0. If it did, we'd have zero in the denominator, and that'd be undefined. So if I take every single term and multiply it by Z, we'd get Z ^2 + 4 equaling -5 Z. Taking everything to one side, we get Z ^2 + 5, Z plus 4 equaling 0. The quantity Z + 1 times the quantity Z + 4 equals zero Z + 1 = 0, so Z is negative one Z + 4 = 0, Z equal -4. Our two solutions are -1 and -4.