Chapter 6 - Systems of Equations and Inequalities - Chapter Review - 6-3 and 6-4 Solving Systems Using Elimination; Applications of Systems - Page 406: 20

One solution $(-1,13)$

$7x + y = 6$ $5x +3y = 34$ $7x + y = 6$ $-3*(7x + y = 6)$ $-21x - 3y = -18$ $-21x-3y = -18$ $5x+3y = 34$ $(-21x+5x-3y+3y) = (-18+34)$ $-16x = 16$ $-16x/-16 = 16/-16$ $x = -1$ $7x+y = 6$ $7*-1 + y = 6$ $-7 + y = 6$ $-7 + y + 7 = 6+7$ $y = 13$