maximal ideal in Lie algebra

Question

suppose that $L$ is leibniz or lie algebra and $M$ is maximal ideal of this.then $L/M$ is simple or one dimensional.why say that one dimensional?

Answer 1

A simple Lie algebra is usually defined to be non-abelian, so a one-dimensional Lie algebra would not usually be considered to be simple.

Answer 2

$L/M$ is simple. a 1-dimensional Lie algebra is simple.