a) 2x+y=5 4x-y=10 y=5-2x 4x-y=10 y=5-2x 4x-5+2x=10 y=5-2x 6x=15/:6 y=5-2x x=2,5 y=5-2•2,5 x=2,5 y=5-5 x=2,5 x=2,5 y=0 b) x+2y= -0,5 3x+4y= -1 x=-0,5-2y 3x+4y= -1 x=-0,5-2y -1,5-6y+4y=-1 x=-0,5-2y -2y=0,5/:(-2) x=-0,5-2y y=-0,25 x=-0,5+0,5 y=-0,25 x=0 y=-0,25
a) 2x+y=5 4x-y=10 y=5-2x 4x-(5-2x)=10 y=5-2x 4x-5+2x=10 y=5-2x 6x=10+5 y=5-2x 6x=15/:6 y=5-2x x=2,5 y=5-2*2,5 x=2,5 y=0 b) x+2y= -0,5 3x+4y= -1 x=-0,5-2y 3*(-0,5-2y)+4y=-1 x=-0,5 - 2y -1,5-6y+4y=-1 x=-0,5-2y -2y=-1+1,5 x=-0,5-2y -2y=0,5/:(-2) x=-0,5-2y y=-0,25 x=-0,5 -2*(-0,25) y=-0,25 x=-0,5 + 0,5 y=-0,25 x=0 c) 2x+2y=4 8x-4y= -2 2x=4-2y/:2 8x-4y=-2 x=2-y 8*(2-y)-4y=-2 x=2-y 16-8y-4y=-2 x=2-y -12y=-18/(-12) x=2-y y=1,5 x=2-1,5 y=1,5 x=0,5 d)5x+10y=5 8x-4y= -2 5x=5-10y/:5 8x-4y=-2 x=1-2y 8*(1-2y)-4y=-2 x=1-2y 8-16y-4y=-2 x=1-2y -20y=-10/:(-20) x=1-2y y=0,5 x=1-2*0,5 y=0.5 y=0 e)x-2y= -10 jedna druga y - 2 = 3 x-2y=-10 0,5y-2=3 x-2y=-10 0,5y=5/:(0,5) x-2y=-10 y=10 x-2*10=-10 y=10 x-20=-10 y=10 x=10 f) 2y-x = 8 4x+3y= 1 -x=8-2y/:(-1) 4x+3y=1 X=-8+2Y 4*(-8+2y)+3y=1 X=-8+2Y -32+8y+3y=1 X=-8+2Y 11y=33/:11 X=-8+2Y y=3 X=-8+2*3 y=3 x=-8+6 y=3 x=-2
a) 2x+y=5 4x-y=10 y = - 2x+5 4x - (-2x+5) = 10 y = 2x+5 4x + 2x - 5 = 10 y = 2x+5 6x = 15/6 y = 2x+5 x = 5/3 y = 2*5/3+5 x = 5/3 y = 10/3 x=5/3 b) x+2y= - 1/2 3x+4y= -1 x = -2y - 1/2 3 ( - 2y - 1/2 ) + 4y = -1 x = - 2y-1/2 -6y - 1.5 + 4y = -1 x=-2y-1/2 2y = 0,5 //2 x = -2y - 1/2 y = 0.25 x = - 2*0.25 - 1/2 y = 0.25 x=0.25 y=0.25 c) 2x+2y=4 8x-4y= -2 2x = -2y + 4 // 2 8X - 4Y = -2 x = - y +2 8*(-y+2) -4y = -2 x = -y +2 -8y + 16 -4y = -2 x = -y +2 - 12y = - 14 //-12 x = -y + 2 y = 14/12 x = - 14/12 +2 y = 7/6 x = - 1 i 1/6 +2 y = 1 i 1/6 x = 5/6 y = 1 i 1/6 d) 5x+10y=5 8x-4y= -2 5x = -10y +5 //5 8x - 4y = -2 x = - 2y +1 8(-2y +1) - 4y = -2 x = - 2y +1 - 16y +8 -4y = -2 x = -2y +1 -20y = - 10 // -20 x = -2y +1 y = 0.5 x = -2 * 0,5 +1 y = 0.5 x = -1 +1 y = 0.5 x = 0 y = 0,5 e) x-2y= -10 1/2 y - 2 = 3 - 2y = -x - 10 //-2 1/2 y - 2 = 3 y = 0,5x + 5 1/2 * (0,5x+ 5) - 2 = 3 y = 0,5x +5 0.25 x + 2,5 - 2 = 3 y = 0.5x +5 0.25x = 3.5 // 0 .25 y = 0.5x +5 x = 14 y = 0,5 * 14 +5 x =14 y = 12 x =14 f) 2y-x = 8 4x+3y= 1 x = - 2y +8 4x+3y = 1 x = - 2y + 8 4(-2y+8) + 3y = 1 x = -2y +8 - 8y + 32 + 3y = 1 x = -2y+8 - 5y = - 31 //-5 x = - 2y +8 y = 31/5 = 6 i 1/5 x = -2 * 6 i 1/5 + 8 y = 6 i 1/5 x = 12.4 + 8 y = 6 i 1/5 x = 20,4 y = 6.2
