a)3x+2y=13 2x+y=11/*(-2) {3x+2y=13 / (dodajemy ) {-4x-2y=-22 / ___________ -x=-9 x=9 2x+y=11 2*9+y=11 18+y=11 y=-7 {x=9 {y=-7 b)5x+3y=0/*2 -x-2y=7/*3 {10x+6y=0 / {-3x-6y=21 /(dodajemy) _______________ 7x=21/:7 x=3 5x+3y=0 5*3+3y=0 15+3y=0 3y=-15/:3 y=-5 {x=3 {y=-5 c)3u+2v=2/*(-2) 5u+4v=6 {-6u-4v=-4/ {5u+4v=6/(dodajemy) ____________________ -u=-2/:(-1) u=2 5u+4v=6 5*2+4v=6 10+4v=6 4v=-4 v=-1 {u=2 {v=-1 d)3s+5t=-6 1,5s-2t=-3/*(-2) {3s+5t=-6/ {-3s+4t=6/ (dodajemy) ___________ 9t=0 t=0 3s+5t=-6 3s+0=-6 3s=-6 s=-2 {t=0 {s=-2 e)5=3x-y 5x-2y=7 {-3x+y=-5/*2 {5x-2y=7 {-6x+2y=-10 / {5x-2y=7/ (dodajemy) ____________ -x=-3 x=3 5x-2y=7 5*3-2y=7 15-2y=7 -2y=-8 y=4 {x=3 {y=4 f)x-3y=5 y+3x=-5/*3 {x-3y=5 / {3y+9x=-15/ (dodajemy) ______________ 10x=-15 x=-1,5 x-3y=5 -1,5-3y=5 -3y=6,5/:(-3) y=-2¹/₆ {x=-1,5 {y=-2¹/₆
