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7^{x+3} -7^{x+2} -7^{x+1} =41*7^{2*x}

3^{x+3}*4^{x+1} -5*3^{x} *4^{x} =1236

Va rog repedeee dau coroana!!!!!!


Răspuns :

Răspuns:

Explicație pas cu pas:

7ˣ⁺³ - 7ˣ⁺² - 7ˣ⁺¹ = 41 x 7²ˣ

7ˣ x 7³ - 7ˣ x 7² - 7ˣ x 7 = 41 x 7²ˣ

7ˣ x 7 x ( 7² - 7 - 1 ) = 41 x 7²ˣ

7ˣ⁺¹ x ( 49 - 7 - 1 ) = 41 x 7²ˣ

7⁽ˣ⁺¹⁾ x 41 = 41 x 7²ˣ  l  : 41

7²ˣ = 7⁽ˣ⁺¹⁾ =>    2 x = x + 1 =>   2 x - x = 1 =>   x = 1

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3ˣ⁺³ x 4ˣ⁺¹ - 5 x 3ˣ x 4ˣ = 1 236

x 3³ x 4ˣ x 4¹ - 5 x ( 3 x 4)ˣ = 1 236

( 3 x 4)ˣ x ( 3³ x 4¹ - 5 ) = 1 236

12ˣ x ( 27 x 4 - 5 ) = 1 236

12ˣ x 103 = 1 236

12ˣ = 1 236 : 103

12ˣ = 12 =>     x = 1

Răspuns:

7^{x+3} -7^{x+2} -7^{x+1} =41*7^{2*x}

7ˣ·7³-7ˣ·7²-7ˣ·7=41·7²ˣ

7ˣ·7·(7²-7-1)=41·7²ˣ

7ˣ⁺¹·(49-7-1)=41·7²ˣ

7ˣ⁺¹·41=41·7²ˣ

7ˣ⁺¹=41:41·7²ˣ

7²ˣ=7ˣ⁺¹

2x=x+1

2x-x=1

x=1

3^{x+3}*4^{x+1} -5*3^{x} *4^{x} =1236

3ˣ·3³·4ˣ·4¹-5·(3·4)ˣ=1236

(3·4)ˣ·(3³·4¹-5)=1236

12ˣ·(27·4-5)=1236

12ˣ·103=1236

12ˣ=1236:103

12ˣ=12¹

x=1