Question

If A = `[(2, 12),(0, 1)], B = [(4, x),(0, 1)]` and A² = B, find the value of x.

Answer 1

A² = `[(2, 12),(0, 1)] xx [(2, 12),(0, 1)]`

= `[(2 xx 2 + 12 xx 0, 2 xx 12 + 12 xx 1),(0 xx 2 + 1 xx 0, 0 xx 12 + 1 xx 1)]`

= `[(4, 24 + 12),(0, 1)]`

= `[(4, 36),(0, 1)]`

A² = B

`[(4, 36),(0, 1)] = [(4, x),(0, 1)]`

So, by comparing:

x = 36