Question

Solve the system:
x + y + z = -1
2x + 2y + 5z = 1
5x + 2y + 3z = 8

what is the value of x in the solution?

Answer 1

By what method are you using. If not your calculator on matricies, then Irecommend the method of determinants.

Answer 2

Use simultaneous equation method:
x=-y-z-1...(1)
Now, the equation 2 become:
2(-y-z-1)+2y+5z=1
-2y-2z-2+2y+5z=1
3z=1+2; z=3
Now equation 1 becomes
x=-y-3-1=-y-4; i.e, x=-y-4....(a)
equation 3 becomes:
5(-y-4)+2y+3(3)=8
-5y-20+2y+9=8
-3y=19; y=-19/3
Now the very first equation becomes
x+2(-19/3)+3=1
x=1-3+38/3=38/3-2=12.7-2=10.7
hence x=10.2