If 3x + 4y – 2z + 9 = 17, 7x + 2y + 11z + 8 = 23 and 5x + 9y + 6z – 4 = 18, then what is the value of x + y + z – 34?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 (i.e. –31)
3x + 4y – 2z = 8 …….. (i)
7x + 2y + 11z = 15 …….. (ii)
5x + 9y + 6z = 22 …….. (iii)
By adding all three equations
15 (x + y + z) = 45
⇒ x + y + z = 3
⇒ x + y + z –34 = 3 – 34 = –31