As you learned in your 8th grade math class and reviewed in your 9th grade Integrated I course, solving systems of linear equations by linear combination.

Both equations were written in Standard form. The addition or fused combination of both equations cancelled out the “x” value, giving us an opportunity to solve for the “y” value. Once this is achieved, Substitute the “y” into the any of the two equations, then solve for “x.” The solution is going to be an ordered pair. (4,-3).

**Solving Systems of Equations by Substitution and Graphing**

We can substitute y in the second equation with the first equation since y = y. The

**solution**of the linear**system**is (1, 6). You can use the**substitution**method even if both equations of the linear**system**are in standard form. Just begin by**solving**one of the equations for one of its variables.The systems of equations can have an array of solutions, for example if lines are parallel, then the system has no solutions.

As the example above indicates, if the system of equations intersect exactly at one point, then the solution is only one ordered pair.

If the linear equations Coincide (meaning the same line) then the system has an infinite number of solution.

Practice on your own

Solve the Systems of Equations by Graphing