а)2х+у=1 5х+2у=0 б) х-2у=7 х+2у=-1

Question

а)2х+у=1 5х+2у=0 б) х-2у=7 х+2у=-1

Answer 1

1)

2x+y=1     y=1-2x

5x+2y=0

5x+2(1-2x)=0

5x+2-4x=0

x=-2

y=1-2(-2)

y=5

x=-2; y=5

2)

x-2y=7   x=7+2y

x+2y=-1

7+2y+2y+1=0

4y=-8

y=-2

x=7+2(-2)

x=3

x=3; y=-2.