Rozwiąż układy równań mrtodą podstawiania : x+5y= -17 3m+n=9 2m-5n= -11 4a-2=b 3a+7b=1,5

1) 2x-y=10 x+5y= -17 -y = 10 -2x x + 5y = -17 y = -10 + 2x x + 5(-10 +2x) = -17 y = 2x-10 x -50 + 10x = -17 y = 2x -10 x +10x = -17 + 50 y = 2x -10 11x = 33 y = 2x -10 x = 33 : 11 y = 2x -10 x = 3 y = 2*3 -10 = 6 -10 = -4 x = 3 y = -4 x = 3 3m+n=9 2m-5n= -11 n = 9 - 3m 2m - 5(9 - 3m) = -11 n = 9 - 3m 2m -45 + 15m = -11 n = 9 -3m 17m = -11 + 45 n = 9 - 3m 17m = 34 n = 9 -3m m = 34 : 17 n = 9 - 3m m = 2 n = 9 -3*2 = 9 -6 = 3 m = 2 n = 3 m = 2 3) 4a-2=b 3a+7b=1,5 b = 4a -2 3a + 7( 4a -2) = 1,5 b = 4a -2 3a +28a - 14 = 1,5 b = 4a -2 31a = 1,5 +14 b = 4a -2 31a = 15,5 b = 4a -2 a = 15,5 : 31 = 0,5 b = 4*0,5 -2 = 2 -2 = 0 a = 0,5 b = 0 a = 0,5

{ a) {2x-y=10 {x+5y=-17 {2x-y=10 {x=-17-5y {2(-17-5y)-y=10 {x=-17-5y {-34-10y-y=10 {x=-17-5y {-11y=10+34 {x=-17-5y {y=-4 {x=-17-5(-4) {y=-4 {x=3 b) {3m+n=9 {2m-5n= -11 {n=9-3m {2m-5n=-11 {n=9-3m {2m-5(9-3m)=-11 {n=9-3m {2m-45+15m=-11 {n=9-3m {17m=34 {n=9-3m {m=2 {n=9-6 {m=2 {n=3 {m=2 c) {4a-2=b {3a+7b=1,5 {b=4a-2 {3a+7(4a-2)=1,5 {b=4a-2 {3a+28a-14=1,5 {b=4a-2 {31a=15,5// przez 31 {b=4a-2 (a=0,5 {b=2-2 (a=0,5 (a=0,5 {b=0

a) {2x-y=10 {x+5y=-17 {2x-y=10 {x=-17-5y {2*(-17-5y)-y=10 {x=-17-5y {-34-10y-y=10 {x=-17-5y {-11y=44 {x=-17-5y {y=-4 {x=-17-5*(-4) {y=-4 {x=3 b) {3m+n=9 {2m-5n=-11 {n=9-3m {2m-5*(9-3m)=-11 {n=9-3m {2m-45+15m=-11 {n=9-3m {17m=34 {n=9-3*2 {m=2 {n=3 {m=2 c) {4a-2=b {3a+7b=1,5 {b=-4a+2 {3a+7*(-4a+2)=1,5 {b=-4a+2 {3a-28a+14=1,5 {b=-4a+2 {25a=12,5 {b=-4*0,5+2 {a=0,5 {b=0 {a=0,5