To understand what Linear Algebra is, first we should understand what a linear equation is. A linear equation is an equation where each value includes no exponentiation (other than $1$) and isn't passed into any functions. For example: $$ x + y + z = 0 $$ $$ a + b + c + d + e = 54 $$ Examples of equations that are not linear include: $$ x^2 + y = 3 $$
A vector is an object that both has a magnitude as well as a direction. It can be denoted in boldface or with a arrow over the name such as $\textbf{a}$ or $\overrightarrow{a} \ $. The magnitude of a vector is how much it moved, and can be denoted like so: $||\textbf{a}||$.
Frank D and Nykamp DQ. "An introduction to vectors".
From Math Insight.
https://mathinsight.org/vector_introduction.
David Dye, Samuel J. Cooper, A. Freddie Page.
"Mathematics for Machine Learning: Linear Algebra". Coursera.
https://www.coursera.org/learn/linear-algebra-machine-learning.
u/ZMeson. "ELI5: What is linear algebra?"
Reddit, 30 Apr. 2018,
https://www.reddit.com/r/explainlikeimfive/comments/8fx48s/comment/dy77x74/.