3 and 4 .Determinants and Matrices
medium

$\alpha, \beta \in \mathbb{R}$ के लिए, माना समीकरण निकाय $ x-y+z=5 $ $ 2 x+2 y+\alpha z=8 $ $ 3 x-y+4 z=\beta $ के अनंत हल है, तब $\alpha$ व $\beta$ निम्न में से किसके मूल है

A

$x ^2-10 x +16=0$

B

$x^2+18 x+56=0$

C

$x^2-18 x+56=0$

D

$x^2+14 x+24=0$

(JEE MAIN-2023)

Solution

$\begin{array}{l}\left|\begin{array}{ccc}1 & -1 & 1 \\ 2 & 2 & \alpha \\ 3 & -1 & 4\end{array}\right|=0 ; 8+\alpha-2(-4+1)+3(-\alpha-2)=0 \\ 8+\alpha+6-3 \alpha-6=0 \\ \alpha=4\end{array}$

Standard 12
Mathematics

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