besides a calculator solution? Your calculator should be able to solve these.
Manually:
add the first and third equations:
5x+y=62
multipy the first equation by 4
12x-8y+4z=36 and subtract equation 2 from that, or
11x-7y=26, and combine that with the original combination:
11x-7y=26
6x+y=62
now multipy the second equation by 7, then add the equations.
3x-2y+z=9
x-y+4z=10
2x+3y-z=53
1 answer