a) x/2=y/3 (*6) x+2,5=y 6(x/2)=6(y/3) x=y-2,5 3x=2y x=y-25/10 x=2/3y 2/3y-y=-25/10 x=2/3y -1/3y=-25/10 x=2/3y y=25/10*3/1 x=2/3y y=75/10 x=2/3*75/10 y=7i1/2 x=150/30=5 y=7i1/2 x=5 b) x/5-y/4=0 (*20) x/2-y/16=5,5 (*16) 20(x/5)-20(y/4)=0*20 16(x/2)-16(y/16)=16*5,5 4x-5y=0 8x-y=88 4x=5y -y=88-8x(*-1) x=5/4y y=-88+8x x=5/4(8x-88) y=8x-88 x=10x-110 y=8x-88 x-10x=-110 y=8x-88 -9x=-110 y=8x-88 x=110/9 y=8(110/9)-88 x=12i2/9 y=97i7/9-88 x=12i2/9 y=9i7/9 c) x+y/3+y/4=-2 (*12) 2x-y/3-3x/4=3/2 (*12) 12x+12(x/3)+12(y/4)=-2*12 12(2x)-12(y/3)-12(3x/4)=12(3/2) 12x+4x+3y=-24 24x-4y-9x=18 3y=-24-16x 15x=18+4y y=-8-16/3x 15x=18+4(-8-16/3x) y=-8-16/3x 15x=18-32-64/3x y=-8-16/3x 15x+21i1/3x=-14 y=-8-16/3x 36i1/3x=-14 y=-8-16/3x x=-14*3/109=-42/109 y=-8-16/3(-42/109)=-8+224/109 x=-42/109 y=-8+2i6/109 x=-42/109 y=-5i103/109 d) 2x-1/5+3y-2/4=2(*20) 3x+1/5-3y+2/4=0(*20) 20(2x)-20(1/5)+20(3y)-20(2/4)=20(2) 20(3x)+20(1/5)-20(3y)+20(2/4)=20(0) 20x-4+60y-10=40 60x+4-60y+10=0 20x=54-60y 60x+14=60y x=54/20-3y 60(54/20-3y)+14=60y x=54/20-3y 162-180y+14=60y x=2i7/10-3y -240y=-176 x=2i7/10-3y y=176/240(skracamy )22/30=11/15 x=2i7/10-3(176/240)=2i7/10-2i2/10=5/10 y=11/15 x=5/10
