Engineering Board Exam Reviewer · Cramer's Rule and Linear Systems · medium
Solve 2x+y+z=9, x-y+2z=6, x+3y-z=4 and find x+y+z.
- 9
- 6
- 4
- 8
Answer
B. 6
Solution
Adding the first two equations: 3x+3z=15 x+z=5. Taking 3×(first) - (third): 5x+4z=23. Substituting x=5-z: 25-z=23 z=2 and x=3. Then y=9-2(3)-2=1. So x+y+z=6.
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