You can put this solution on YOUR website! x+y+z= 11……………….(1)
2x+5y+2z= 31………….(2)
-x+7y-3z= 1…………….(3)
Multiply (1) by -2 and add to (2)
-2x-2y-2z= -22
2x+5y+2z= 31
----------------------
3y=9
Y=9/3
Y=3
Multiply (1) by 3 and add to (3)
3x+3y+3z= 33
-x+7y-3z= 1
---------------------------
2x+10y=34 ………………….(4)
Put the value of y in (4)
2x+10(3)=34
2x+30=34
2x=34-30
2x=4
x=4/2
x=2
Now put the value of x and y in any of three equations (1),(2),(3)
We put in (1)
x+y+z= 11
2+3+Z=11
5+Z=11
Z=11-5
Z=6
SO x=2, y=3 and z=6
To check our result we can put values of x,y,z in any of three equation i.e. (1),(2) or (3)
First put the values of x,y,z in (1)
x+y+z= 11
2+3+6=11
11=11
Now in (2)
2x+5y+2z= 31
2(2)+5(3)+2(6)=31
4+15+12=31
31=31
In last in (3)
-x+7y-3z= 1
-2+7(3)-3(6)=1
-2+21-81=1
21-20=1
1=1
Note: There is no need use all three equations to check our result. One equation is enough to verify our results.
