Question

4,5,6 va rog dau 100 de puncte​

Answer 1

4.

a = (3²¹ + 3²⁰ + 3¹⁹) : 39

= 3¹⁹(3² + 3 + 1) : 39

= 3¹⁹(9 + 3 + 1) : 39

= 3¹⁹× 13 : 39

= 3¹⁹ × 1/3

= 3¹⁸

= (3⁹)² patrat perfect

5.

p = 3⁷¹×4⁶²

3⁷¹ = 3⁶⁸ₓ3³ => (u)3⁷¹ = (u)3³ = 7

4⁶² = 4⁶⁰ₓ4² => (u)4⁶² = (u)4² = 6

(u)3⁷¹×4⁶² = (u) 7×6 = (u) 42 = 2

6.

7ˣ + 7ˣ⁺² = 2450

7ˣ(1 + 7²) = 2450

7ˣ(1 + 49) = 2450

(7ˣ)×50 = 2450

7ˣ = 2450 : 50

7ˣ = 49

7ˣ = 7²

x = 2

Answer 2

Explicație pas cu pas:

4 )

a = ( 3²¹ + 3²⁰ + 3¹⁹ ) : 39

a = 3¹⁹( 3² + 3 + 1 ) : 39

a = 3¹⁹( 9 + 3 + 1 ) : 39

a = 3 · 3¹⁹ : 39

a = 3¹⁹ : 3

a = 3¹⁹⁻¹

a = 3¹⁸

a = ( 3⁹ )² - > pătrat perfect

5 ) p = 3⁷¹ · 4⁶²

3⁷¹

3¹ = 3

3² = 9

3³ = 27

3⁴ = 81

.....

u ( 3¹ ) = 3

u ( 3² ) = 9

u ( 3³ ) = 7

u ( 3⁴ ) = 1

.........

71 : 4 = 17 r 3

u ( 3⁷¹ ) = 7

4⁶²

4¹ = 4

4² = 16

62 : 4 = 15 r 2

u ( 4⁶² ) = 6

p = 7 · 6

p = 42

Ultima cifră este 2 !

6 ) 7ˣ + 7ˣ⁺² = 2450

7ˣ( 1 + 7² ) = 2450

7ˣ( 1 + 49 ) = 2450

7ˣ · 50 = 2450

7ˣ = 2450 : 50

7ˣ = 49

7ˣ = 7²

x = 2