## Elementary Linear Algebra 7th Edition

$x_{1}$= 3 ; $x_{2}$=-2
(1) 0.05$x_{1}$ - 0.03$x_{2}$ = 0.21 (2) 0.07$x_{1}$ + 0.02$x_{2}$ = 0.17 100$R_{1}$→$R_{1}$ 100$R_{2}$→$R_{2}$ (3) 5$x_{1}$ - 3$x_{2}$ = 21 (4) 7$x_{1}$ + 2$x_{2}$ = 17 2$R_{1}$→$R_{1}$ 3$R_{2}$→$R_{2}$ (5) 10$x_{1}$ - 6$x_{2}$ = 42 (6) 21$x_{1}$ + 6$x_{2}$ = 51 $R_{1}$+$R_{2}$→$R_{2}$ 31$x_{1}$ = 93 $x_{1}$ = 3, plug this value into (5) 10(3) - 6$x_{2}$ = 42 30 - 6$x_{2}$ = 42 -6$x_{2}$ = 12 $x_{2}$ = -2