Verified Solution • 2025–26 Session moderate

QJEEM22Ma95ad: JEE Main 2022 Mathematics - Class 12 JEEM22Ma95ad Solution: The number of values of for which the system of equations : x + …

The number of values of α\alpha for which the system of equations :

x + y + z = α\alpha

α\alpha x + 2 α\alpha y + 3z = −- 1

x + 3 α\alpha y + 5z = 4

is inconsistent, is

Multiple Choice Options

  • A 0
  • B 1
  • C 2
  • D 3

Step-by-Step Verified Solution

Δ=∣1amp;1amp;1αamp;2αamp;31amp;3αamp;5∣\Delta=\left|\begin{array}{ccc}1 & 1 & 1 \\ \alpha & 2 \alpha & 3 \\ 1 & 3 \alpha & 5\end{array}\right|

amp;=1(10α−9α)−1(5α−3)+1(3α2−2α)amp;=α−5α+3+3α2−2αamp;=3α2−6α+3\begin{aligned}&=1(10 \alpha-9 \alpha)-1(5 \alpha-3)+1\left(3 \alpha^{2}-2 \alpha\right) \\\\&=\alpha-5 \alpha+3+3 \alpha^{2}-2 \alpha \\\\&=3 \alpha^{2}-6 \alpha+3\end{aligned}

For inconsistency Δ=0\Delta=0 i.e. α=1\alpha=1

Now check for α=1\alpha=1

x+y+z=1...(i)x+y+z=1\quad\quad...(i)

x+2y+3z=−1...(ii)x+2 y+3 z=-1\quad\quad...(ii)

x+3y+5z=4...(iii)x+3 y+5 z=4\quad\quad...(iii)

By (ii) ×2−\times 2- (i) ×1\times 1

x+3y+5z=−3x+3 y+5 z=-3

so equations are inconsistent for α=1\alpha=1

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