Question

ДАЮ 50 БАЛЛОВ, СРОЧНО ПОМОГИТЕ ПД

Answer 1

2.

$\left \{ {{x-5y=8} \atop {2x+4y=30}} \right. \\\left \{ {{x=8+5y} \atop {2x+4y=30}} \right. \\\\2(8+5y) + 4y=30\\16 + 10y + 4y = 30\\14y = 14\\y=1;x=13\\\text{OTBET: x=13; y=1 }$

$\left \{ {{5a-3b=14} \atop {2a+b=10}} \right. \\\left \{ {{5a-3b=14} \atop {b=30-2a}} \right. \\5a - 3 (10-2a) = 14\\5a-30+6a=14\\11a = 44\\a =4\\b=2\\\text{OTBET: a =4; b=2}$

3

$\left \{ {{4x+2y=5} \atop {4x-6y=-7}} \right. \\\left \{ {{4x+2y=5} \atop {-4x+6y=+7}} \right. \\\\8y=12\\y=1.5\\x = 0.5\\\text{OTBET: x = 0.5; y= 1.5}$

1. Линии параллельные. Решения нет