Python assignment $2-$ Cramer's Rule

Ax $=$ b

Implement a function called cramer that takes in a matrix $($A$)$ and a vector $($b$)$ as a inputs, compute the solution to the linear system as output of the function. Note that the matrix A is a n x n matrix and b is a vector with length n$,$ where n can be any number between $2$ to $100.$

For example:

$10$x$1+40$x$2+70$x$3=300$

$20$x$1+50$x$2+80$x$3=360$

$30$x$1+60$x$2+80$x$3=390$

Solution$/$output should be $[1,2,3]$