2x-y=4 x+2y=7 -y=4-2x / *(-1) x=7-2y y=2x-4 x=7-2y y=2(7-2y)-4 x=7-2y y=14-4y-4 x=7-2y 4y+y=10 x=7-2y 5y=10 /:5 x=7-2y y=2 x=7-2*2 y=2 x=7-4=3 spr. x+2y=7 2x-y=4 3+2*2=7 2*3-2=4 7=7 4=4 b) 3x+y=-1 4x+3y=2 y=-1-3x 4x+3(-1-3x)=2 y=-1-3x 4x-3-9x=2 y=-1-3x -5x=2+3 /:(-5) y=-1-3x x=-1 y=-1-3*(-1) x=-1 y=-1+3=2 x=-1 spr 3x+y=-1 4x+3y=2 3*(-1)+2=-1 4*(-1)+3*2=2 -1=-1 2=2 c) 5x-y=1,5 3x+6y+4,2 ???? mysle ze ostatni + to rówmna sie -y=1,5-5x /*(-1) 3x+6y=4,2 y=-1,5+5x 3x+6(-1,5+5x)=4,2 y=-1,5+5x 3x-9+30x=4,2 y=-1,5+5x 33x=9+4,2 /:33 y=-1,5+5*0,4 x=0,4 y=0.5 x=0,4 spr 5x-y=1,5 3x+6y+4,2 5*0,4-0,5=1,5 3*0,4+6*0,5=4,2 1,5=1,5 4,2=4,2 d) 6x+2y=7 9x-4y=0 2y=7-6x /:2 9x-4y=0 y=3,5-3x 9x-4(3,5-3x)=0 y=3,5-3x 9x-14+12x=0 y=3,5-3x 21x=14 /*1/21 y=3,5-3*2/3 x=2/3 y=3,5-2=1,5 x=2/3 spr 6x+2y=7 9x-4y=0 6*2/3+2*1,5=7 9*2/3-4*1,5=0 7=7 0=0 e)x+4y=1 x-8y=-1 x+4y=1 x=-1+8y -1+8y+4y=1 x=-1+8y 12y=2 / *1/12 x=-1+8y y=1/6 x=-1+8*1/6 y=1/6 x=2/6 spr x+4y=1 x-8y=-1 2/6+4*1/6=1 2/6-8*1/6=-1 6/6=1 -6/6=-1
a) 2x-y=4 x+2y=7 2x-y =4 x = 7-2y 2( 7-2y) - y = 4 x = 7-2y 14 - 4y -y = 4 x = 7-2y -5y = -10 x = 7-2y y=2 x= 7- 2*2 y = 2 x = 3 Odp. b) 3x+y=-1 4x+3y=2 y= -1-3x 4x+3(-1-3x)=2 y=-1-3x 4x-3-9x=2 y=-1-3x -5x=2+3 /:(-5) y=-1-3x x=-1 y=-1-3*(-1) x=-1 y=-1+3=2 x=-1 y =2 x = -1 Odp. c) 5x-y=1,5 3x+6y = 4,2 -y=1,5-5x /*(-1) 3x+6y=4,2 y=-1,5+5x 3x+6(-1,5+5x)=4,2 y=-1,5+5x 3x-9+30x=4,2 y=-1,5+5x 33x=9+4,2 /:33 y=-1,5+5*0,4 x=0,4 y=0,5 x=0,4 Odp. d) 6x+2y=7 9x-4y=0 2y=7-6x /:2 9x-4y=0 y=3,5-3x 9x-4(3,5-3x)=0 y=3,5-3x 9x-14+12x=0 y=3,5-3x 21x=14 /*1/21 y=3,5-3*2/3 x=2/3 y=3,5-2=1,5 x=2/3 y = 1,5 x = 2/3 Odp. e)x+4y=1 x-8y=-1 x+4y=1 x=-1+8y -1+8y+4y=1 x=-1+8y 12y=2 / *1/12 x=-1+8y y=1/6 x=-1+8*1/6 y=1/6 x=2/6 Odp.
