Question

Use the elimination method to solve the following system of equations.

x + 3y – z = 2
x – 2y + 3z = 7
x + 2y – 5z = –21

Answer 1

x + 3y – z = 2
x – 2y + 3z = 7
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0x +5y -4z = -5

x – 2y + 3z = 7
x + 2y – 5z = –21
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0x -4y + 8z = 28 or -2y+4z=14

then

+5y -4z = -5
-2y +4z = 14
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3 y +0z = 9

y = 3
now go back up and get x and z