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If \(\begin{bmatrix}a + b&2\\[0.3em]7&ab\\[0.3em]-3&4\end{bmatrix} = \begin{bmatrix}6&2\\[0.3em]7&8\\[0.3em]-3&4\end{bmatrix}\) then find ‘a’ and ‘b’. |
Answer» \(\begin{bmatrix}a + b&2\\[0.3em]7&ab\\[0.3em]-3&4\end{bmatrix} = \begin{bmatrix}6&2\\[0.3em]7&8\\[0.3em]-3&4\end{bmatrix}\) On comparing, a + b = 6 ……(i) ab = 8 From equation (i) and (ii), a(6 – a)= 8 ⇒ 6a – a2 – 8 = 0 ⇒ a2 – 2a – 4a + 8 = 0 ⇒ a2 – 2a – 4a + 8 = 0 (a – 2)(a – 4) = 0 So, a = 2, 4 From ab = 8 we get b = 4, 2 |
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