\(a,\left(2x-16\right)^7=128\\ \Rightarrow\left(2x-16\right)^7=2^7\\ \Rightarrow2x-16=2\\ \Rightarrow2x=18\\ \Rightarrow x=9\\ b,x^3.x^2=2^8:2^3\\ \Rightarrow x^5=2^5\\ \Rightarrow x=5\\ c,3^{x-3}-3^2=2.3^2\\ \Rightarrow3^{x-3}-9=18\\ \Rightarrow3^{x-3}=27\\ \Rightarrow3^{x-3}=3^3\\ \Rightarrow x-3=3\\ \Rightarrow x=6\)

THANK YOU NHA 

Ta có:

A=\(\frac{3^{10}.11+3^8.45}{3^9.16}\)

A=\(\frac{3^{10}.11+3^{10}.5}{3^9.16}\)

A=\(\frac{3^{10}.\left(11+5\right)}{3^9.16}\)

A=\(\frac{3^{10}.16}{3^9.16}\)

A=3

Hok tốt

\(\frac{3^{10}.11+3^8.45}{3^9.16}\) 

=\(\frac{59049.11+6561.45}{19683.16}\) 

=\(\frac{649539+295245}{314928}\) 

=\(\frac{944784}{314928}\) 

=3 

\(\Rightarrow]\) K CHO MÌNH NHA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!PLEASE

\(x^2+11x+28=0\)

\(x^2+4x+7x+28=0\)

\(x\left(x+4\right)+7\left(x+4\right)=0\)

\(\left(x+4\right)\left(x+7\right)=0\)

\(\Rightarrow\hept{\begin{cases}x+4=0\\x+7=0\end{cases}}\)

\(\Rightarrow\hept{\begin{cases}x=-4\\x=-7\end{cases}}\)

Đặt \(A=\frac{1.2+2.4+3.6+4.8+5.10}{4+6.8+9.12+12.16+15.20}\)

\(\Rightarrow A=\frac{1.\left(1+2\right)+2.\left(1+2\right)+3.\left(1+2\right)+4.\left(1+2\right)+5.\left(1+2\right)}{4+2.\left(3+4\right)+3.\left(3+4\right)+4.\left(3+4\right)+5.\left(3+4\right)}\)

\(\Rightarrow A=\frac{\left(1+2+3+4+5\right).\left(1+2\right)}{4+\left(2+3+4+5\right).\left(3+4\right)}\)

\(\Rightarrow A=\frac{\left(1+5\right).5:2.\left(1+2\right)}{4+\left(2+5\right).4:2.\left(3+4\right)}\)

\(\Rightarrow A=\frac{6.5:2.3}{4+7.4:2.7}=\frac{45}{4+98}=\frac{45}{102}=\frac{15}{34}\)

Vậy \(A=\frac{15}{34}\)

Chúc bn học tốt

a) 3(x + 5) + 5(x + 7) = 58

3x + 15 + 5x + 35 = 58

8x + 50 = 58

8x = 58 - 50

8x = 8

x = 8 : 8

x = 1

b) 3(x + 7) - 2(x + 3) = 16

3x + 21 - 2x - 6 = 16

x + 15 = 16

x = 16 - 15

x = 1

MÌNH ĐANG CẦN GẤP

115 + 3 . ( x - 2 ) = 295

           3 . ( x - 2 ) = 295 - 115

           3 . ( x - 2 ) = 180

                  x - 2 = 180 : 3 

                  x - 2 = 60

                  x      = 60 + 2

                  x      = 62

16 : 2 . x = 9

             x = ko tính được

20 - ( x +14 ) = 5

           x + 14 = 20 - 5 

           x + 14  = 15

           x           = 15 - 14

            x         = 11

57 : ( 9 . x - 27 ) = 0

 vì số nào chia 0 thì bằng 0 mà 27 : 9 = 3 nên

x = 3  

Tìm x:

115+3.(x-2)= 295               16:2.x= 9                                      20-(x+14)=5                                 57:(9x-27)=0

3.(x-2)= 295-115                  2.x= 16:9                                     x+14= 20-5                                   9x-27= 0

3.(x-2)= 180                         2.x= 16/9.                                     x+14= 15.                                          9x= 27

 x-2= 180:3                            x= \(\frac{16}{9}:2\)                               x= 15-14                                            x= 27:9

x-2= 60                                   \(x=\frac{16}{9}.\frac{1}{2}\)                          x= 1                                                 x= 3

x= 60+2                                   \(x=\frac{8}{9}\)

x= 62