[latex] left { {{-7x-3y=10} atop {5x+4y=-9}} ight. [/latex] [latex] left { {{2x-2y=4} atop {2x+3y=18}} ight. [/latex] [latex] left { {2x+3y=5(x-3)} atop {4(x+5)-2(y-3=34}} ight. [/latex] potrzebuje na jutro

-28x-12y=40 15x+12=-27 -13x= 13 x=-1 5*(-1)+4y=-9 4y=-9+5 4y=-4 y=-1 -2x+2y=-4 2x+3y=18 5y=14 y=14/5 2x-2*14/5=4 2x=9 3/5 x=4 4/5 2x+3y=5x-15 4x+20-2y+6=34 -3x+3y=-15 4x-2y=8 -6x+6y=-30 12x-6y=24 6x=-6 x=-1 12*(-1)-6y=24 -6y=36 y=-6

-7x-3y=10  / *4 5x+4y=-9  /* 3 -28x-12y=40 15x+12y=-27 ....................... -13x=13 x=-1 -7x-3y=10 -7*(-1)-3y=10 -3y=3 y=-1 x=-1 y=-1 Spr. -7x-3y=10  -7*(-1)-3*(-1)=10  10=10  L=P 5x+4y=-9  5*(-1)+4*(-1)=-9  -9=-9  L=P 2. 2x-2y=4 / *(-1) 2x+3y=18 -2x+2y=-4 2x+3y=18 .................... 5y=14 y=2  4/5 2x-2y=4 2x-2*2  4/5=4 2x=9  3/5 x=4  4/5 x=4  4/5 y=2  4/5 Spr. 2x-2y=4   2*5  4/5 - 2*2  4/5 =4   48/5-28/5=4   4=4  L=P 2x+3y=18  2*4  4/5+3 * 2  4/5 = 18    48/5+42/5=18   18=18  L=P 3. 2x+3y=5x-15 4x+20-2y+6=34 -3x+3y=-15  /*2 4x-2y=8  /*3 -6x+6y=-30 12x-6y=24 ............. 6x=-6 x=-1 -3x+3y=-15 -3*(-1)+3y=-15 3y=-15-3 3y=-18 y=-6 x=-1 y=-6 Spr. 2x+3y=5x-15    2*(-1)+3*(-6)=5*(-1)-15   -20=-20   L=P 4x+20-2y+6=34   4*(-1)+20-2*(-6)+6=34   34=34  L=P