It is known that \(A\ne B\ne I\) and \(A^{-1}\ne B\).
Their answers are given as:
Abhay: \(6 AB\),
Bina : \(7 AB-BA\),
Chhaya: \(8 AB\),
Devesh: \(7 BA - AB\).
Who answered it correctly?
Question:
Four friends Abhay, Bina, Chhaya and Devesh were asked to simplify \(4~AB+3(AB+BA)-4~BA,\) where A and B are both matrices of order \(2\times2\).