Вопрос пользователя:
решите систему уравнений 2(3х+2у)+9=4х+21 2х+10=3-(6х+5у)
Илюха отвечает:
1) 2(3х+2у)+9=4х+21
6x + 4y + 9 – 4x – 21= 0
2x+ 4y – 12 = 0
2(x+2y-6) = 0
x + 2y – 6 = 0
x + 2y = 6
2) 2х+10=3-(6х+5у)
2х + 10 – 3 + 6х + 5у = 0
8x + 5y +7 = 0
8x + 5y = -7
x + 2y = 6 *(-8)
8x + 5y = -7
-8x – 16y = -48
8x + 5y = -7
-11y = -55
y = 5