If you want to see the details of elimination, a good place to go is
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
2x+y+2z=25
3x-y+6z=48
5x+2y+4z=55
I got stuck after step 2 of trying to eliminate the first two equations where do I go from their and would kindly like full explanation of how to solve it so I can practice it out. Thank you :)
2 answers
A preliminary glance at the coefficients tells you that the y's would be the easiest to eliminate.
As a matter of fact, you can do it in your head:
add the first two equations:
5x + 8z = 73 , #4
mentally double the 2nd and add to the third:
11x + 16z = 151 , #5
double #4 ---> 10x + 16z = 146
subtract from #5
------> x = 5
back in #4
25+8z = 73
8z =48
z = 6
back in #1
2x+y+2z = 25
10 + y + 12 = 25
y = 3
As a matter of fact, you can do it in your head:
add the first two equations:
5x + 8z = 73 , #4
mentally double the 2nd and add to the third:
11x + 16z = 151 , #5
double #4 ---> 10x + 16z = 146
subtract from #5
------> x = 5
back in #4
25+8z = 73
8z =48
z = 6
back in #1
2x+y+2z = 25
10 + y + 12 = 25
y = 3
1 answer