How do you solve this system of equations: #3x + 3y - 6z = 8; 2x + y - z = 7; - x - y + 2z = 4#?

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Answer 1 · 2018-04-21T23:23:16

#x=7/2#

# y=15/2#

#z=15/2#

#3x+3y-6z=8# ## ## ## #.......... # #A#

#2x+y-z=7# ## ## ## ## ## # # # # # .......... # #B#

#-x-y+2z=4# ## ## ## # ##.......... # #C#
# #
# #

#A+B+C = 4x+3y-5z = 19#
# #
# #
add B and C you can erase #y# term

#B+C = x+z=11#

#C = -x-y+2z = -(x+y)+2z= -11+2z=4#
# #
# #
# #
#:. 2z = 15, z=15/2#

#:. x+15/2=11, x=7/2#

#:. 2x + y-z=7#

# # # # # # # # # # # # #14/2+ y - 15/2=7#

# # # # # # # # # # # # # # #y-1/2=7#

#:. y=15/2#