Chapter 6 - Systems of Equations and Inequalities - 6-3 Solving Systems Using Elimination - Practice and Problem-Solving Exercises - Page 378: 7

(4,5)

Add the equations to eliminate y. $3x+3y=\ \ 27$ $\underline{\ x-3y=-11}$ $4x\ \ \ \ \ \ \ \ =\ \ \ 16$ Solve for x. $4x=16$ $4x\div4=16\div4$ $x=4$ Substitute 4 for x in either equation and solve for y. $x-3y=-11$ $4-3y=-11$ $4-3y-4=-11-4$ $-3y=-15$ $-3y\div-3=-15\div-3$ $y=5$