Determinant of [4779]\left[\begin{array}{cc}4 & 7\\7 & 9\end{array}\right]

The calculator will find the determinant of the square 22x22 matrix [4779]\left[\begin{array}{cc}4 & 7\\7 & 9\end{array}\right], with steps shown.

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A

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Your Input

Calculate 4779\left|\begin{array}{cc}4 & 7\\7 & 9\end{array}\right|.

Solution

The determinant of a 2x2 matrix is abcd=adbc\left|\begin{array}{cc}a & b\\c & d\end{array}\right| = a d - b c.

4779=(4)(9)(7)(7)=13\left|\begin{array}{cc}4 & 7\\7 & 9\end{array}\right| = \left(4\right)\cdot \left(9\right) - \left(7\right)\cdot \left(7\right) = -13

Answer

4779=13\left|\begin{array}{cc}4 & 7\\7 & 9\end{array}\right| = -13A