Question

ПОМОГИТЕ ПОЖАЛУЙСТА СРОЧНО

Answer 1

во втором задании нет решения

Answer 2

1.

$left { {{x+y=20} atop {x-3y=4}} right. => left { {{x=20-y} atop {20-y-3y=4}} right. => left { {{x=20-y} atop {4y=16}} right. => left { {{x=20-6} atop {y=6}} right. => left { {{x=14} atop {y=4}} right.$

Ответ: 14 и 4

2.

$left { {{0,3x+2y=3} atop {-3x-20y=1}} right. => left { {{2y=3-0,3x} atop {-3x-10(3-0,3x)=1}} right. => left { {{2y=3-0,3x} atop {-3x-30+0,3x=1}} right. => left { {{2y=3-0,3x} atop {-2,7x=31}} right. => left { {{2y=3-0,3(310/27)} atop {x=-310/27}} right. => left { {{2y=3+31/9} atop {x=-310/27}} right. => left { {{y=2*58/9} atop {x=-310/27}} right. => left { {{y=12} atop {x=-310/27}} right.$

Ответ: имеет 2 решения.