6x-17y=11//6 -5x+15y=10 x=-2i5/6y+1i5/6 -5(-2i5/6y+1i5/6)+15y=10 14 i 1/6y-9i1/6+15y=10 19i1/6y=19i1/6 //19i1/6 y=1 -5x+15*1=10 -5x+15=10 -5x=-5 //(-5 x=1 2x-3y=6 y-2x=2 y=2+2x 2x-3(2+2x)=6 2x-6-6x=6 -4x=12 //(-4 x=-3 y-2*(-3)=2 y+6=2 y=-4 12x-6y=6 7x+y=8 y=8-7x 12x-6(8-7x)=6 12x-48-42x=6 -30x=54//(-30) x=-1 i4/5 y=8-(-1i4/5) y=9 i 4/5
a) 6x-17y=11 -5x+15y=10/:(-5) 6x-17y=11 x-3y=-2 6x-17y=11 x=-2+3y 6(-2+3y)-17y=11 x=-2+3y 12+18y-17y=11 x=-2+3y y=23 x=-2+3*23 y=23 x=67 b) 2x-3y=6 y-2x=2 2x-3y=6 y=2+2x 2x-3(2+2x)=6 y=2+2x 2x-6-6x=6 y=2+2x -4x=12 y=2+2x x=-3 y=2+2*(-3) x=-3 y=4 c) 12x-6y=6/:6 7x+y=8 2x-y=1 7x+y=8 y=-1+2x 7x-1+2x=8 y=-1+2x 9x=9 y=-1+2x x=1 y=-1+2*1 x=1 y=1 x=1
