Answer:subtraction property
Step-by-step explanation:
Two a negative and a negative makes a positive so it would be x+6=18 so u do the opposite on both sides so it would be subtraction
In general, a solution of a system in two variables is an ordered pair that makes BOTH equations true. In other words, it is where the two graphs intersect, what they have in common. So if an ordered pair is a solution to one equation, but not the other, then it is NOT a solution to the system
Greetings!
"<span>What is the general process for solving an equation with one variable?"...
Typically when solving an equation with one variable, your objective is to
isolate the variable on one side of the equation. This can be done adding/subtracting number to cancel them out on one side. You can also multiply/divide coefficients in order to isolate a variable.
Example:</span>

<span>Add
-4 to both sides to isolate the variable.
</span>

<span>
Simplify.
</span>

Divide both sides by
2 to isolate the variable on one side.


Hope this helps.
-Benjamin