## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

The two nongraphical methods covered in this section are Substitution and Eliminitaion. Both have the goal of producing ONE equation in ONE variable as the first step to solving the system. The substitution method works by isolating a variable, and then substituting into the other equation. The elimination method works by applying the addition principle. (Adding equal amounts to both sides of an equation results in an equivalent equation). To eliminate terms containing a variable, we multiply each equation (if needed) with selected coefficients to make the two terms opposite in terms of addition. Adding the equations results in 0$\times$(the variable), eliminating it temporarily. Fill the blank with: opposite