2x-y=10 x+5y=-17 2x-y=10 x=-5y-17 2*(-5y-17)-y=10 x=-5y-17 -10y-34=10 x=-5y-17 -10y=34+10 x=-5y-17 -10y=44 /-10 x=-5y-17 y=-4,4 x=-5*(-4,4)-17 y=-4,4 x=-22-17 y=-4,4 x=-39
a) 2x-y=10/*5 x+5y=-17 10x-5y=50 x+5y=-17 x+10x+5y-5y=50-17 11x=33 x=3 3+5y=-17 5y=-20 y=-4 x=3 b) 3m+n=9/*5 2m-5n=-11 15m+5n=45 2m-5n=-11 15m+2m+5n-5n=45-11 17m=34 m=2 3*2+n=9 6+n=9 n=3 m=2 c) 4a-2=b/*7 3a+7b=1,5 28a-14=7b 3a+28a-14=1,5 31a=15,5 a=0,5 0,5*4-2=b b=0 a=0,5 d) 5x=4-2y 4x+y=3/*2 8x+2y=6 4-2y=5x 8x+2y+4-2y=5x 8x+4=5x 5x-8x=4 -3x=4 x=-4/3 4-2y=5*-4/3 -2y=-20/3 -4 2y=20/3 +4 y=10/3 +2 y=16/3 x=-4/3 e) 6x-3y=9 x+5y=-9,5 /*-6 -6x-30y=57 6x-3y=9 6x-6x-30y-3y=9+57 -33y=66 y=-2 x+2*-2=-9,5 x-4=-9,5 x=-5,5 y=-2
a) 2x-y=10 x+5y=-17 y=-10+2x x+5(-10+2x)=-17 y=-10+2x x-50+10x=-17 y=-10+2x 11x=-17+50 y=-10+2x x=3 y=-10+6 y=-4 b) 3m+n=9 2m-5n=-11 n=9-3m 2m-5(9-3m)=-11 2m-45+15m=-11 17m=34 m=2 n=9-3*2 n=3 c) 4a-2=b 3a+7b=1,5 3a+7(4a-2)=1,5 3a+28a-14=1,5 31a=15,5 a=0,5 b=4*0,5-2 b=0 d) 5x=4-2y 4x+y=3 y=3-4x 5x=4-6+8x -3x=-2 x=2/3 y=3-4*2/3 y=1/3 e) 6x-3y=9 x+5y=-9,5 x=-9,5-5y 6(-9,5-5y)-3y=9 -57-30y-3y=9 -33y=66 y=-2 x=-9,5-5*-2 x=0,5
