Determinants Level 6: 2x2 mastery (+/-15). 2x2 diagonal difference. 1. Diagonal formula1. Diagonal formulaDown diagonal minus up diagonal.determinant equals12-749ad minus bc equals 136down: 12 x 9 = 108up: -7 x 4 = -28108 - (-28) = 136|12 -7; 4 9|: 12x9 - (-7)x4 = 136.
