To solve a system of equations involving three variables (x, y, z), we can utilize matrices and convert them into row echelon form. This process involves organizing the coefficients of the equations into a matrix and performing row operations to achieve a specific format where the leading coefficients (or pivots) are 1, and all entries below these pivots are 0.
Start by constructing a matrix from the coefficients of the equations. For example, if we have the equations:
1. \(2x + 4y + 6z = 24\)
2. \(x + 5y + 12z = 60\)
3. \(3x + 6y + 15z = 20\)
We can represent this as:
\[\begin{bmatrix}2 & 4 & 6 & | & 24 \\1 & 5 & 12 & | & 60 \\3 & 6 & 15 & | & 20\end{bmatrix}\]
The first step is to swap rows if necessary to position a leading 1 in the top left corner. After swapping rows, we can perform row operations to eliminate the entries below the leading 1. For instance, to eliminate the 2 below the leading 1, we can replace row 2 with the result of adding a multiple of row 1 to it. This process continues until we achieve a matrix in row echelon form.
Once in row echelon form, we can back substitute to find the values of x, y, and z. For example, if we reach a form like:
\[\begin{bmatrix}1 & 5 & 12 & | & 60 \\0 & 1 & 3 & | & 16 \\0 & 0 & 1 & | & -\frac{16}{3}\end{bmatrix}\]
We can interpret this as:
1. \(x + 5y + 12z = 60\)
2. \(y + 3z = 16\)
3. \(z = -\frac{16}{3}\)
Substituting the value of z into the second equation allows us to solve for y:
y + 3(-\frac{16}{3}) = 16
y - 16 = 16
y = 32
Next, substitute the values of y and z back into the first equation to solve for x:
x + 5(32) + 12(-\frac{16}{3}) = 60
x + 160 - 64 = 60
x + 96 = 60
x = -36
Thus, the solution to the system of equations is:
x = -36, y = 32, z = -\frac{16}{3}.
This methodical approach of using matrices and row operations not only simplifies the process of solving systems of equations but also provides a clear pathway to finding the values of multiple variables efficiently.