If A = [a
_{
ij
}
] is a matrix of order 2 × 2, such that |A| = −15 and C
_{
ij
}
represents the cofactor of a
_{
ij
}
, then find a
_{
21
}
c
_{
21
}
+ a
_{
22
}
c
_{
22
}

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.