\(3^{x+4}+3^{x+2}=270\)  

\(3^{x+2+2}+3^{x+2}=270\) 

\(3^{x+2}\cdot3^2+3^{x+2}\cdot1=270\) 

\(3^{x+2}\left(3^2+1\right)=270\) 

\(3^{x+2}\cdot10=270\) 

\(3^{x+2}=270:10\) 

\(3^{x+2}=27\) 

\(3^{x+2}=3^3\) 

\(x+2=3\) 

\(x=1\)

                                                                 Bài giải

\(3^{x+4}+3^{x+2}=270\)

\(3^{x+2}\left(3^2+1\right)=270\)

\(3^{x+2}\cdot10=270\)

\(3^{x+2}=27=3^3\)

\(x+2=3\)

\(x=1\)

\(3^{x+1}+3^{x+2}-2.3^x=270\\ \Leftrightarrow3^x.3+3^x.3^2-2.3^x=270\\ \Leftrightarrow3^x.\left(3+3^2-2\right)=270\\ \Leftrightarrow3^x.10=270\\ \Leftrightarrow3^x=270:10\\ \Leftrightarrow3^x=27\\ \Leftrightarrow3^x=3^3\\ \Leftrightarrow x=3\)

a,(x-5)^2=25

(x-5)^2=5^2

=>x-5=5

x=5+5=10

Vậy x=10

b,(2x+1)^2=25

(2x+1)^2=5^2

=>2x+1=5

2x=6

x=6:2

x=3

Vậy x=3

c,(3x-2^4).7^3=2.7^4

3x-2^4=2.7^4:7^3=14

3x=16+14=30

x=30:3

x=10

Vậy x=10

d,2.3^x+3^2+x=891

b: =>12-x=-7

hay x=19

a)

\(\text{( 25 – 2x )³ : 5 – 3^2 = 4^2}\)

\(\text{( 25 – 2x )³ : 5 – 9 = 16}\)

\(\text{( 25 – 2x )³ : 5 = 16 + 9}\)

\(\text{( 25 – 2x )³ : 5 = 25}\)

\(\text{( 25 – 2x )³ = 25 . 5}\)

\(\text{( 25 – 2x )³ = 125}\)

\(\text{( 25 – 2x )³ = 5³}\)

\(\text{25 – 2x = 5}\)

\(\text{2x = 25 – 5}\)

\(\text{2x = 20}\)

\(\text{x = 10}\)

\(\text{________________________________________}\)

b)

\(\text{2.3^x = 10.3^12 + 8.27^4}\)

\(\text{2.3^x = 10.3^12 + 8.(3^3)^4}\)

\(\text{2.3^x = 3^12 . (10+8)}\)

\(\text{2.3^x = 3^12 . 18}\)

\(\text{3^x = 3^12 . 18:2}\)

\(\text{3^x = 3^12 . 9}\)

\(\text{3^x = 3^12 . 3^2}\)

\(\text{3^x = 3^14}\)

\(\text{=> x=14}\)

Bài 1:

29.(85-47)+85.(47-29)

=29.38+85.18

=1102+1530

 =2632

BÀI 2

a, 15x = -75

        x =( -75) : 15

        x = -5

Vậy x= -5                                                            

b,-5x+8=-27

     -5x    = -27 - 8 

       -5x= -35

          x =-35 : -5

           x = 7

Vậy x = 7

c,3.(17 + x ) = - 42

       17 + x     = - 42 : 3

         17 + x    = -14

                x      = - 14 - 17

                 x = -31

Vậy x = - 31

d,-10 -( 2x -16) = 0

           2x - 16 = 10-0

           2x - 16 = 10

            2x = 10 +16

             2x = 26

                 x = 26 : 2

                  x = 13

 Vậy x = 13

e,( mik ko bít làm)

f,( tự làm nghen bạn)