Given:
System of linear equations.
Step-by-step explanation:
System 1:

The above system of equations can be simplified ELIMINATION BY SUBTRACTION.
System 2:

The above system of equations can be simplified using the SUBSTITUTION METHOD.
System 3:

The above system of the equation can be simplified using ELIMINATION BY SUBTRACTION.
System 4:

The above system of the equation can be simplified using ELIMINATION BY SUBTRACTION.
System 5:

The above system of the equation can be simplified using ELIMINATION BY MULTIPLICATION.