Correct Answer - Option 4 : 5

\(x^{(y^{z} )}=1 \) …… (i)

∴ x = 1, because for any value of y^{z}

If x = 1, then, \(x^{y^{z} }\) remain 1.

∴ x = 1

\(y^{z^{x }}=125\)…… (ii)

We can verify value from this equation by putting x = 1, y = 5 and z = 3

⇒\(5^{3^{1}}=125\)

Again,

\(z^{y^{x}}=243 \) …… (iii)

⇒\(z^{y^{x}}=3^{5^{1}}=243\)

∴ It is clear that –

⇒ x = 1, y = 5 and z = 3

The value of 9x + 10y – 18z

⇒ 9 + 50 – 54

⇒ 5