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Find x, if $\left|\begin{array}{ccc}{4} & {3} & {9} \\ {3} & {-2} & {7} \\ {11} & {4} & {x}\end{array}\right|=0$

written 6.3 years ago by teamques10 ★ 70k

modified 3.7 years ago by krithikkm200 • 10

engineering mathematics

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written 6.3 years ago by teamques10 ★ 70k

Solution:

$\left|\begin{array}{ccc}{4} & {3} & {9} \\ {3} & {-2} & {7} \\ {11} & {4} & {x}\end{array}\right|=0$

$4(-2 x-28)-3(3 x-77)+9(12+22)=0$

$\therefore-8 x-112-9 x+231+306=0$

$\therefore-17 x+425=0$

$\therefore x=25$

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