Odpowiedź :
(7⁹:49⁻⁵)² × 7⁻⁴⁰=
=(7⁹:(7²)⁻⁵)² × 7⁻⁴⁰=
=(7⁹:7⁻¹⁰)² × 7⁻⁴⁰=
=(7⁹⁺¹⁰)² × 7⁻⁴⁰=
=(7¹⁹)² × 7⁻⁴⁰=
=7³⁸ × 7⁻⁴⁰=7⁻²
=(7⁹:(7²)⁻⁵)² × 7⁻⁴⁰=
=(7⁹:7⁻¹⁰)² × 7⁻⁴⁰=
=(7⁹⁺¹⁰)² × 7⁻⁴⁰=
=(7¹⁹)² × 7⁻⁴⁰=
=7³⁸ × 7⁻⁴⁰=7⁻²