a) x + 4y = -2 3x - 8y = 10 x=-2-4y 3(-2-4y)-8y=10 x=-2-4y -6-12y-8y=10 x=-2-4y -20y=16 x=-2-4y y=-0,8 x=-2+3,2 y=-0,8 x=1,2 y=-0,8 b) x - 2y = 3 -2x + y = 0 x=3+2y -2(3+2y)+y=0 x=3+2y -6-4y+y=0 x=3+2y -3y=6 x=3+2y y=-2 x=3-4 y=-2 x=-1 y=-2 c) 2x + y = 9 5x - 4y = 3 2x=9-y 2,5(9-y)-4y=3 2x=9-y 22,5-2,5y-4y=3 2x=9-y -6,5y=-19,5 2x=9-y y=3 2x=9-3 y=3 2x=6 y=3 x=3 y=3 d) 3x - 2y = 5 2x - y = 4 2x=4+y 1,5(4+y)-2y=5 2x=4+y 6+1,5y-2y=5 2x=4+y -0,5y=-1 2x=4+y y=2 2x=4+2 y=2 2x=6 y=2 x=3 y=2 e) 2x + 9y = -9 -3x - 3y = 8 2x=-9-9y -1,5(-9-9y)-3y=8 2x=-9-9y 13,5+13,5y-3y=8 2x=-9-9y 10,5y=5,5 2x=-9-9y y=11/21 2x=-9-4 i 5/7 y=11/21 2x=4 i 2/7 y=11/21 x=2 i 1/7 y=11/21 f) 2x + 3y = 4 8x - 5y = -1 2x=4-3y 4(4-3y)-5y=-1 2x=4-3y 16-12y-5y=-1 2x=4-3y -17y=-17 2x=4-3y y=1 2x=4-3 y=1 2x=1 y=1 x=0,5 y=1
a) x + 4y = -2 3x - 8y = 10 x=-2-4y 3(-2-4y)-8y=10 -6-12y-8y=10 -20y=16 y=-0,8 x=-2-4(-0,8) x=-2+3,2 x=1,2 b) x - 2y = 3 -2x + y = 0 x=3+2y -2(3+2y)+y=0 -6-4y+y=0 -3y=6 y=-2 x=3+2(-2) x=3-4 x=-1 c) 2x + y = 9 5x - 4y = 3 y=9-2x 5x-4(9-2x)=3 5x-36+8x=3 13x=39 x=3 y=9-2*3 y=9-6 y=3 d) 3x - 2y = 5 2x - y = 4 -y=4-2x y=-4+2x 3x-2(-4+2x)=5 3x+8-4x=5 -x=-3 x=3 y=-4+2*3 y=-4+6 y=2 e) 2x + 9y = -9|:2 -3x - 3y = 8 x+4,5y=-4,5 x=-4,5-4,5y -2(-4,5-4,5y)+9y=-9 9+9y+9y=-9 18y=-18 y=-1 x=-4,5-4,5(-1) x=-4,5+4,5 x=0 f) 2x + 3y = 4|:2 8x - 5y = -1 x+1,5y=2 x=2-1,5y 8(2-1,5y)-5y=-1 16-12y-5y=-1 -17y=-17 y=1 x=2-1,5*1 x=2-1,5 x=0,5
