If \(\begin{vmatrix} 2 & -4 \\ x & 9 \end{vmatrix} = 58\), find the value of x.
A
10
B
30
C
14
D
28
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
\(\begin{vmatrix} 2 & -4 \\ x & 9 \end{vmatrix} = 58\)
\(\implies (2 \times 9) - (-4 \times x) = 58\)
\(18 + 4x = 58 \implies 4x = 58 - 18 = 40\)
\(x = 10\)
Source: Myschool Past Questions Archive (Record #55021)