Solve the equation for x.
-$$\left| \begin{array} { l l }
x & 3 \
2 & 1
\end{array} \right| = 12$$
A) $\{ 18 \}$
B) $\{ 4 \}$
C) $\{ - 2 \}$
D) $\{ 12 \}$

Question

Solve the equation for x.
-$$\left| \begin{array} { l l } 
x & 3 \
2 & 1
\end{array} \right| = 12$$
A) $\{ 18 \}$
B) $\{ 4 \}$
C) $\{ - 2 \}$
D) $\{ 12 \}$

Quizplus · Accepted Answer

The determinant of a 2x2 matrix is calculated as $ad - bc$, where $a, b, c, d$ are the elements of the matrix starting from the top left corner. So, for the given matrix, the determinant is $x(1) - 3(2) = x - 6$. Setting this equal to 12 gives $x - 6 = 12$, solving for $x$ gives $x = 18$.

Solve the Equation for X ∣x321∣=12\left| \begin{array} { l l } x & 3 \\2 & 1\end{array} \right| = 12​x2​31​​=12

Solve the Equation for X $\left| \begin{array} { l l } x & 3 \\2 & 1\end{array} \right| = 12$