Question

va rog ex 5
dau coroana

Answer 1

a) x + 2y = 20 | x3

3x + 6y = 60

y + 3z = 30 | x3

3y + 9z = 90

3y + 9z = 90

3x + 6y = 60

------------------------(+)

3x + 9y + 9z = 150

b) 8x + 6y - 6z =

2(4x + 3y - 3z)

x + 2y = 20 | x2

2x + 4y = 40

2x + 4y = 40

y + 3z = 30

-------------------(-)

2x + 4y - ( y + 3z ) = 10

2x + 4y - y - 3z = 10

2x + 3y -3z = 10 | x2

2(4x + 3y - 3z) = 20

8x + 6y - 6z = 20