Solve one equation for one variable. The first equation has a coefficient of 1 on the *y*, so we'll solve the first equation for *y* to get In the "other" equation, perform substitution to get rid of the variable we solved for in (1). We substitute for *y* in the equation 2*y* + 6*x* = -8 to get After substituting, solve the "other" equation. We simplify to get -6*x* -8 + 6*x* = -8 Combining the *x* terms, we get -8 = -8. We know this statement is true, because we just lost $8 the other day, and now we're $8 poorer. We left the money in our pants and sent them through the washer. We won't make that mistake again. Since we've arrived at a statement that's always true, these two lines are really the same line, and every point on the line is a solution. |