Question
Mathematics Question on graphical solution of linear inequalities in two variables
If the system of linear equations
2 x + y – z = 7
x – 3 y + 2 z = 1
x + 4 y + δ z = k , where δ, k ∈ R
has infinitely many solutions, then δ + k is equal to:
A
–3
B
3
C
6
D
9
Answer
3
Explanation
Solution
The correct option is(B): 3
2 x + y – z = 7
x – 3 y + 2 z = 1
x + 4 y + δ z = k
⇒ 6 – k = 0 ⇒ k = 6
δ + k = -3 + 6 = 3