Apply forward elimination to this system of linear equations to put it into the upper triangular form.

• Write each row operation you make to solve the problem.
• Write the matrix and the right-hand side after each row operation, for example, the initial matrix and right-hand side can be represented as:

A = [ [-3, 2, 1], [6, -4, 1], [-12, 9, 6] ] b = [5, -12, 21]