Question

Find which of the variables x, y, z and u represent rational numbers and which irrational numbers:

(i) x² = 5

(ii) y² = 9

(iii) z² = .04

(iv) u² = 17/4

Answer 1

(i) x² = 5

On solving, we get

⇒ x = ± √5

Hence, x is an irrational number.

(ii) y² = 9

On solving, we get

⇒ y = ± 3

Hence, y is a rational number.

(iii) z² = .04

On solving, we get

⇒ z = ± 0.2

Hence, z is a rational number.

(iv) u² = 17/4

On solving, we get

⇒ u = ± √17/2

√17 is irrational.

Hence, u is an irrational number