Question

I really need help on 2 !!

Answer 1

x=2

y=-1

z=3

Explanation:

X = 7+2y-z

3(7+2y-z)+y-z=2

21+6y-3z+y-z=2

21+7y-4z=2

7y-4z=-19 (subtract both side by 21)

2(7+2y-z)+3y+2z=7

14+4y-2z+3y+2z=7

14+7y=7

7y=-7 (subtract both side by 14)

y=-1 (divide both side by 7)

{7y-4z=-19

{y=-1

7.-1 - 4z=-19

-7-4z=-19

-4z=-12

Z=3

x=7+2y-z (y=-1 z=3)

x=7+2.-1 - 3

x=7-2-3

x=2