Question

If $A=\begin{bmatrix} 1 & 2 & x \\\ 0 & 1 & 0 \\\ 0 & 0 & 1 \end{bmatrix}$, $B=\begin{bmatrix} 1 & -2 & y \\\ 0 & 1 & 0 \\\ 0 & 0 & 1 \end{bmatrix}$ and AB = I3, where I3 is the unit matrix of order 3 × 3, then x + y is equal to :

• A. 0
• B. -1
• C. 2
• D. -2

Answer 1

Answer: (A)

0

Answer 2

The correct option is (A) :0.