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Mathematics

If A = [42−3−9]\begin{bmatrix} 4 & 2 \ -3 & -9 \end{bmatrix}, then the value of (-3)A is:

  1. [−8−4618]\begin{bmatrix} -8 & -4 \ 6 & 18 \end{bmatrix}

  2. [−12−6918]\begin{bmatrix} -12 & -6 \ 9 & 18 \end{bmatrix}

  3. [−12−6927]\begin{bmatrix} -12 & -6 \ 9 & 27 \end{bmatrix}

  4. [−1269−27]\begin{bmatrix} -12 & 6 \ 9 & -27 \end{bmatrix}

Matrices

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Answer

Given,

[42−3−9]\begin{bmatrix} 4 & 2 \ -3 & -9 \end{bmatrix}

Solving for -3A:

⇒−3[42−3−9]⇒[−12−6927]\Rightarrow -3\begin{bmatrix} 4 & 2 \ -3 & -9 \end{bmatrix} \\[1em] \Rightarrow \begin{bmatrix} -12 & -6 \ 9 & 27 \end{bmatrix}

Hence, option 3 is the correct option.

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