Find x in the following system x2y2z5 xy5z6 3xy2z7 Answer 1

Find x in the following system

x+2y-2z=5

x+y-5z=6

-3x+y-2z=7

(Answer: -1, please show work)

x+2y-2z=5............(i)

x+y-5z=6.............(ii)

-3x+y-2z=7............(iii)

2*(ii)-5*(iii) gives

2x+2y-10z-[-15x+5y-10z]=12-35

or,17x-3y=-23...............(iv)

(iii)-(i) gives

-3x+y-2z-[x+2y-2z]=7-5

or,-4x-y=2.....(v)

(iv)-3*(v) gives

17x-3y-[-12x-3y]=-23-6

or, 29x=-29 or x=-1 [answer]