Question

If A = `[(1 , -2),(2, -1)] and "B" = [(3, 2),(-2, 1)]` Find 2B – A² 

Answer 1

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

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

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

= `[(6, 4),(-4, 2)]`

A² = A x A = `[(1, -2),(2, -1)] [(1, -2),(2, -1)]`

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

= `[(-3, 0),(0, -3)]`

∴ 2B – A² = `[(6, 4),(-4, 2)] - [(3-, 0),(0, -3)]`

= `[(6 - (-3), 4 - 0),(-4 - 0, 2 - (-3))]`

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

= `[(9, 4),(-4, 5)]`.