Solve the equation for x.
-$$\left| \begin{array} { r r }
- 2 & 5 \
1 & x
\end{array} \right| = - 3$$
A) $\{ - 1 \}$
B) $\{ - 3 \}$
C) $\{ 4 \}$
D) $\varnothing$

Question

Solve the equation for x.
-$$\left| \begin{array} { r r } 
- 2 & 5 \
1 & x
\end{array} \right| = - 3$$
A) $\{ - 1 \}$
B) $\{ - 3 \}$
C) $\{ 4 \}$
D) $\varnothing$

Quizplus · Accepted Answer

The determinant of the matrix is found by multiplying the diagonal elements and subtracting the product of the off-diagonal elements: $(-2 \cdot x) - (5 \cdot 1) = -2x - 5$. Setting this equal to -3 gives $-2x - 5 = -3$, solving for $x$ gives $x = -1$.

Solve the Equation for X ∣−251x∣=−3\left| \begin{array} { r r } - 2 & 5 \\1 & x\end{array} \right| = - 3​−21​5x​​=−3

Solve the Equation for X $\left| \begin{array} { r r } - 2 & 5 \\1 & x\end{array} \right| = - 3$