An appropriate description of the substitution method would be

The substitution method is one of several methods used for solving systems of equations.  If, for example, you have a system of two linear equations in x and y, you could solve either equation for x and subst. the resulting expression in y into the other equation.  This eliminates x and allows you to find the value of y.

Example:  Solve this system of linear equations:

3x + 4y = 7
2x  +  y  = -3

Let's solve the 2nd equation for y:  y = -2x - 3.  Now substitute -2x -3 for y in the other equation:     3x + 4(-2x-3) = 3   (Note how y disappears!)

Then 3x -8x - 12 = 3; -5x = 15  => x=-3.

Again we substitute:  Subst. -3 for x in either of the given equations and solve for y.

Write your solution in the form (x,y).

These are examples of the subst. method and its applications.

Line the mark up so you will find your answer