Simultaneous equations like 𝒚 = 2𝒙 - 1 and 𝒚 = 𝒙 + 1 can be represented graphically. To solve the equations graphically, the two lines 𝒚 = 𝒙 + 1 and 𝒚 = 2𝒙 - 1 are drawn on the same diagram.

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.