Q481
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?
A.
-28
B.
-14
C.
-31
AnswerD.
-45
Answer: Option C
Solution
Answer: Option C
Solution:
3x + 4y - 2z + 9 = 17 . . . . . . . . (1)7x + 2y + 11z + 8 = 23 . . . . . . . (2)
5x + 9y + 6z - 4 = 18 . . . . . . . . (3)
____________________________
15x + 15y + 15z + 13 = 58
(By adding equation (1), (2) & (3))
15(x + y + z) = 45
x + y + z = 3
x + y + z - 34 = 3 - 34 = -31