Solving a System of Linear Equations in Two Variables - Problem 9

For any given system of equations, you have a choice of 3 (or perhaps 4) methods for solving: graphing, substitution, elimination, and maybe matrices, if you've learned them. All methods will work for any given problem- you'll get the correct answer - but often one method would be easier than another. In short, use graphing if the lines are already in y = mx+b form and you have a ruler and graph paper handy, use substitution if one of your variables has a coefficient of one, use elimination if the coefficients of one of your variables are additive inverses, and use matrices if you are allowed the use of technology. Always check your solution point by plugging the x and y values back into both original equations.