3⁴ . 3^x + 3^{x + 1} = 243

3⁴ . 3^x + 3^x . 3¹ = 243

3^x . ( 3⁴ + 3¹ ) = 243

3^x . ( 81 + 3 ) = 243

3^x . 84 = 243

3^x = 243 : 84

3^x = ..............  =  3^....

Suy ra x = .......

Good luck. ( Phần cuối tự tính )

\(A=1+2^2+2^3+....+2^{60}\)

\(\Rightarrow2A=2+2^3+3^4+...+2^{61}\)

\(\Rightarrow A=2^{61}-2-1\)

Đặt B=2^2+2^3+....+2^60

<=>2B=2^3+2^4+....+2^61

<=>2B-B=(2^3+2^4+....+2^61)-(2^2+2^3+....+2^60)

<=>B=2^61-2^2

<=>B=2^61-4

=>A=1+B

<=>A=1+2^61-4

=>A=2^61-3

vậy A=2^61-3

(1+12).12:2=78

Có:

\(A=3^1+3^2+3^3+...+3^{33}\)

\(=\left(3^1+3^3+3^5+...+3^{99}\right)+\left(3^2+3^4+3^6+...+3^{98}\right)\)

         Có 50 số hạng                                               Có: 49 số hạng

\(=\left(3^1+3^3\right)+\left(3^5+3^7\right)+...+\left(3^{97}+3^{99}\right)+\left(3^2+3^4\right)+\left(3^6+3^8\right)+...+\left(3^{94}+3^{96}\right)+3^{98}\)

\(=3\left(1+9\right)+3^5\left(1+9\right)...+3^{97}\left(1+9\right)+3^2\left(1+9\right)+3^6\left(1+9\right)+...+3^{94}\left(1+9\right)+3^{98}\)

\(=3.10+3^5.10+...+3^{97}.10+3^2.10+3^6.10+...+3^{94}.10+3^{98}\)

\(=10\left(3+3^5+...+3^{97}\right)+10\left(3^2+3^6+...+3^{94}\right)+3^{98}\)không chia hết cho 10.

4^3=64

4.49=196

( 96 : 24 ) ³ = 4³ = 64

2² . 7² = 4 . 49 = 196

Chúc bạn học tốt!!!

A=2(2⁰+2¹)+2³(2⁰+2¹)+...+2¹¹(2⁰+2¹)

=2. 3 + 2³.3+...+2¹¹.3

=3.(2+2³+...+2¹¹)

Do 3 chia hết cho 3 ==> 3.(2¹+2³+...+2¹¹) chia hết cho 3

có hihihihi

có nha bạn . nhớ k cho mình nhé