8i

Certainly! In mathematics, "i" represents the imaginary unit, defined as the square root of -1. The expression "8i" is simply eight times that imaginary unit, meaning it’s a complex number with no real part but a imaginary part of 8. Complex numbers like this help in fields such as engineering and physics to solve equations that don't have solutions among real numbers alone. So, "8i" is a number that exists on the imaginary axis in the complex plane, illustrating how quantities can have both real and imaginary components.