Q46 / 160 · TS EAMCET 2022 (19 Jul Shift 2) · Mathematics

Let $\alpha, \beta, \gamma$ be real numbers. If $\left(\begin{array}{ccc}7 & 5 & \alpha \\ \beta & 2 & 11 \\ 3 & \gamma & 1\end{array}\right)\left(\begin{array}{l}1 \\ 3 \\ 2\end{array}\right)=\left(\begin{array}{c}\alpha+\beta \\ -2 \alpha+\beta-2 \gamma \\ \alpha+2 \beta+3 \gamma\end{array}\right)$ then $100+\frac{2 \alpha+11 \beta}{\gamma}=$

  • Correct answer
    A
    27
  • B
    -25
  • C
    225
  • D
    -227

Solution

We have $\left[\begin{array}{ccc}7 & 5 & \lambda \\ \beta & 2 & 11 \\ 3 & \gamma & 1\end{array}\right]\left[\begin{array}{l}1 \\ 3 \\ 2\end{array}\right]=\left[\begin{array}{c}\alpha+\beta \\ -2 \alpha+\beta-2 \gamma \\ \alpha+2 \beta+3 \gamma\end{array}\right]$ On solving we get, $$ \begin{aligned} & \alpha=-13, \beta=9, \gamma=-1, \text { then, } 100+\frac{2 \alpha+11 \beta}{\gamma} \\ & \Rightarrow 100-73=27 \end{aligned} $$ On solving we get, $$ \begin{aligned} & \alpha=-13, \beta=9, \gamma=-1, \text { then, } 100+\frac{2 \alpha+11 \beta}{\gamma} \\ & \Rightarrow 100-73=27 \end{aligned} $$

Hence, the correct answer is option: 'A'.

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