Question

Let `"A" = [(4 , -2),(6 , -3)], "B" = [(0 , 2),(1 , -1)] and "C" = [(-2 , 3),(1 , -1)]`. Find A² - A + BC

Answer 1

`"A" = [(4 , -2),(6 , -3)], "B" = [(0 , 2),(1 , -1)] and "C" = [(-2 , 3),(1 , -1)]`.

∴ A² = `[(4 , -2),(6 , -3)][(4 , -2),(6 , -3)]`

= `[(16 - 12, -8 +6),(24 - 18, -12 + 9)]`

∴ A² = `[(4 , -2),(6 , -3)]`

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

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

Now A² - A + BC
= `[(4 , -2),(6 , -3)] - [(4 , -2),(6 , -3)] + [(2 , -2),(-3 , 4)]`

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