Question

Modular arithmetic
Pls a little explaine it

Answer 1

Explanation:

(72)¹⁴³ ≡ x (mod 7)

Since 72 ≡ 2 (mod 7),

72³ ≡ 2³ (mod 7) ≡ 1 (mod 7).

Therefore (72)¹⁴³ = (72³)⁴⁷ * (72²)

≡ 1⁴⁷ * 4 (mod 7) ≡ 4 (mod 7).

The answer is A.