Question

решите систему уравнений 3-(х-2у)-4у=18, 2х-3у+3=2(3х-у)

Answer 1

3-(x-2y)-4y=18
3-x+2y-4y=18
-x-2y=18-3
-x-2y=15
-(x+2y)=15
x+2y= -15

2x-3y+3=2(3x-y)
2x-3y+3=6x-2y
2x-6x-3y+2y= -3
-4x-y= -3
-(4x+y)=-3
4x+y=3

{x+2y= -15
{4x+y=3

4x+y=3
y=3-4x

x+2(3-4x)=-15
x+6-8x=-15
-7x=-15-6
-7x=-21
x=3

y=3-4*3
y=3-12
y= -9

Ответ: (3; -9).

Answer 2

3-(х-2у)-4у=18
3-х+2у-4у=18