Systems of Equations
When you use graphing to solve the system of equations you need to change them into slope intercept form (y=mx+b). After that you need to plug it in to some sort of calculator. Once you have done that go to the graph section and find the intersection point.
In substitution you need to isolate one variable (in this case X). Once you have isolated one variable plug the answer of that variable into the other problem. Solve the equasion that you plugged it into. Next you should get the other variables answer. Plug that answer into the first equation and solve. You the should get the answer to the variable you were solving for first.
When using Elimination you take the like terms and cancel them out using addition. For example if you have 1 and -1 then add them together it comes out to equal 0.
Write a System
To write a system you will need two equations with two variables. The two equations should rely on one another.
The down payment is $15 for this certain problem
Which is best to use.
If an equation is in slope intercept is best to use graphing. If one variable is solved then you should use substitution. If all your variables are lined up with each other then it is best to use elimination.
Their are three answers you can get. One solution, No solution, and infinitely many. If your answer doesn't make scene then it is no solution. if the answer is exactly equal on both sides then it is infinitely many. One solution is what you normally get.