1) 2x +2y -x = -6; 3x-x +y =0;
y = -2x; x + 2y = -6;
x -4x = -6;
3x = 6;
x =2; y = -4;
2) 3x + 6y -y = 27; 4x + 4y - 3x = 23;
3x + 5y = 27; x + 4y = 23;
x = 23 -4y; 69 - 12y + 5y = 27;
7y = 42;
y = 6; x = -1;
3) 5x - 2y - 8 = 0; 12x +18 -y = 41;
y = 12x -23; 5x -24x + 46 - 9 = 0;
19x = 38;
x = 2; y = 1;
4) 2x + 3x + 3y = 11; 7x + 21y - 6x = -59;
x = -59 -21y; -295 -105y +3y = 11;
102y = -306;
y = -3; x =4;
Для проверки можете подставить данные значения в уравнения.
1498.
1) 4x + 3y = 5; x = 3 + y;
12 + 7y = 5;
7y = -7;
y = -1; x = 2;
2) x = 7 + y; 35 + 2y = 1;
2y = -34;
y = -17; x =10;
3) y = -2 -2x; 6x - 10 -10x = 6;
4x = -16;
x = -4; y = 6;