In some simultaneous equations neither the two coefficients of \(x\) nor the coefficients of \(y\) match. You will need to find numbers to multiply each equation by so that one pair of coefficients ...

Solution: det (A) = −5, and for n×n matrix adj (A) has determinant (det A)^ (n−1). Here n = 3, so det (B) = (−5)^ (2) = 25.