Question
If the system of linear equations 2 x+y-z=7 x-3 y+2 z=1 ; x+4 y+ z=k where , k R has infinitely many solutions, then +k is equal to:
BITSAT
Mathematics
Determinants
2024
BITSAT 2024 (Memory Based Paper 1)
BITSAT Mathematics Question (2024) — Solution
Options
- A. -3
- B. 3
- C. 6
- D. 9
Answer
B. 3
Step-by-step solution
For getting infinite solutions D =0, D _1= D _2= D =0 then check all the three equations Let = | array ccc 2 & 1 & -1 \\ 1 & -3 & 2 \\ 1 & 4 & array |=0 =-3 And _1= | array ccc 7 & 1 & -1 \\ 1 & -3 & 2 \\ k & 4 & -3 array |=0 k=6 +k=3
Related: Mathematics — Determinants · All PYQ Banks