If A = [(3/5,4/5),(x,3/5)] and A^T = A^-1, then the value of x is ... (a) -4/5 (b) -3/5 (c) 3/5 (d) 4/5

Question

If A = \(\begin{bmatrix} 3/5 &4/5 \\[0.3em] x&3/5 \\[0.3em] \end{bmatrix}\) and A^T = A^-1, then the value of x is ...

(a) -4/5

(b) -3/5

(c) 3/5

(d) 4/5

Answer 1

(a) -4/5

A = \(\begin{bmatrix} 3/5 &4/5 \\[0.3em] x&3/5 \\[0.3em] \end{bmatrix}\)

Comments

How det.A becomes 1

---

X=29/8,-11/8