Question

If matrix A = `[(2, 2),(0, 2)]` and A² = `[(4, x),(0, 4)]`, then the value of x is ______.

Options

• 2

• 4

• 8

• 10

Answer 1

If matrix A = `[(2, 2),(0, 2)]` and A² = `[(4, x),(0, 4)]`, then the value of x is 8.

Explanation:

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

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

= `[(4, 8),(0, 4)]`

Compare with given A²

A² = `[(4, x),(0, 4)]`

x = 8