What is the x- value of x-2y plus z equals -9 3y-2z equals 4 2x plus y plus 5z equals -5?

Answer 1

x-(x-2y)+z=-9

3y-2z=4

2x+y+5z=-5

x-(x-2y)+z=-9 --distribute negative through bracket--> x-x+2y+z=-9

x-x+2y+z=-9 --combine like terms (x)--> 2y+z=-9

2y+z=-9 --isolate z--> z=-9-2y

substitute z into second equation:

3y-2(-9-2y)=4 --multiply -2 through bracket--> 3y+18+4y=4

3y+18+4y=4 --subtract 18 from both sides--> 3y+4y=-14

3y+4y=-14 --combine like terms--> 7y=-14

7y=-14 --divide both sides by 7--> y=-2

Substitute value of y into simplified first equation:

z=-9-2(-2) --multiply through the bracket--> z=-9+4

z=-9+4 --combine like terms--> z=-5

Substitute values of y and z into third equation:

2x+(-2)+5(-5)=-5 --multiply through brackets--> 2x-2-25=-5

2x-2-25=-5 --combine like terms--> 2x-27=-5

2x-27=-5 --add 27 to both sides--> 2x=22

2x=22 --divide both sides by 2--> x=11

x=11, y=-2, z=-5