Question

If A = `[(2, 1),(0, -2)] and "B" = [(4, 1),(-3, -2)], "C" = [(-3, 2),(-1, 4)]` Find A² + AC – 5B

Answer 1

A = `[(2, 1),(0, -2)]`

B = `[(4, 1),(-3, -2)]`

C = `[(-3, 2),(-1, 4)]`

A² + AC – 5B

= `[(2, 1),(0, -2)] [(2, 1),(0, -2)] + [(2, 1),(0, -2)] [(-3, 2),(-1, 4)] -5[(4, 1),(-3, -2)]`

(Substituting the values from questions)

= `[(4 + 0, 2 - 2),(0 + 0, 0 + 4)] + [(-6 - 1, 4 + 4),(0 + 2,  0 - 8)] - 5[(4, 1),(-3, -2)]`

= `[(4, 0),(0, 4)] + [(-7, 8),(2, -8)] - [(20, 5),(-15, -10)]`

= `[(4 - 7 - 20, 0 + 8 - 5),(0 + 2 + 15, 4 - 8 + 10)]`

= `[(-23, 3),(17, 6)]`