Which of the following statements is TRUE?

W) \(-7\) is not a prime number

X) \(e^{i\pi}=-e^{-i\pi}\) [e to the power of quantity I times pi equals negative e to the power of quantity negative I times pi]

Y) All pairs of perpendicular lines in the Cartesian plane have slopes that are negative reciprocals of each other

Z) There is no number \(a\) such that \(\log(-a)\)[log of negative a] exists.
W) \(-7\) IS NOT A PRIME NUMBER