1. Multiply by 5/40 and sum with 2nd row
SYSTEM OF LINEAR EQUATIONS:
Gaussian Elimination Method
Example:
x x x3
/ /
Multiply by -1/4 and sum with 1st row
Sum with 1st row
Multiply by 5/40 and sum with 2nd row
/ /4
System of linear equations is frequently encountered in the solution of various engineering problems containing more than one unknown variables. In linear algebra, the Gaussian elimination method (also known as row reduction) is used to solve the system of linear equations. The method is a sequence of operations performed on the associated matrix of coefficients.

2. A x b clc;clear; a=[3,2,0;12,13,6;-3,8,9]; b=[14;40;-28]; x=inv(a)*b
System of Linear Equations:
System of linear equations can be written in matrix form as A x b
Solution with Matlab:
x =
2.0000
4.0000
clc;clear;
a=[3,2,0;12,13,6;-3,8,9];
b=[14;40;-28];
x=inv(a)*b