Question

A=[3 2 -1 7] B= [-1 5 3 6]
Show that
(A+B) (A-B) = A²-B²
​

Answer 1

Step-by-step explanation:

A = [3 2 -1 7] B = [-1 5 3 6]

A+B = [2 7 2 13]

A-B = [4 -3 -4 1]

(A+B)(A-B) = [2 7 2 13][4 -3 -4 1] = [-20 1 -44 7]

A² = [3 2 -1 7][3 2 -1 7] = [7 20 -10 47]

B² = [-1 5 3 6][-1 5 3 6] = [16 25 15 51]

A²-B² = [-9 -5 -25 -4]

Hence, (A+B)(A-B) ≠ A²-B²

Answer 2

This is a question of matrix.