Question

if the value of determinants 4,-5,3,X is 31, then find the value of x​

Answer 1

$\binom{4 \: - 5}{ 3 \: x} = 31$

=

$4x + \: 15 = 31 \\ 4x = 31 - 15 \\ x = \frac{16}{4} \\ x = 4$