5^x . 5^{x + 1} . 7 = 875

\(\Rightarrow\) 5^{2x + 1} = 875 : 7 = 125

\(\Rightarrow\) 5^{2x + 1} = 5³

\(\Rightarrow\) 2x + 1 = 3

\(\Rightarrow\) 2x = 2

\(\Rightarrow\) x = 1

5 + 3^{x + 1} = 86

\(\Rightarrow\) 3^{x + 1} = 81

\(\Rightarrow\) 3^{x + 1} = (\(\pm\)3)⁴

\(\Rightarrow\) x + 1 = \(\pm\)3

\(\Rightarrow\) x = 2, -4

2^x + 2^{x + 1} = 96

\(\Rightarrow\) 2^x + 2^x . 2 = 96

\(\Rightarrow\) 2^x . 3 = 96

\(\Rightarrow\) 2^x = 32

\(\Rightarrow\) 2^x = 2⁵

\(\Rightarrow\) x = 5

12x - 10x + 54 = 86
\(\Rightarrow\)12x - 10x = 86 - 54
\(\Rightarrow\)2x = 32 
\(\Rightarrow\)x = 32 : 2
\(\Rightarrow\) x= 16
 

12x-10x+54=86

=(12-10)x+54=86

(12-10)x      =32

     2x            =32

       x            =32chia2

       x            =16

a) 86 - x < 86 - 4

     86 - x < 82

             x < 86 - 82

             x < 4

b) hình như đề bài sai hay sao á

không phải sai đau

tra loi tiep cho minh di

8. Find the value of 14 x 14 + 2 x 14 x 86 + 86 x 86.

\(=\left(14\times3\right)+\left(86\times3\right)+2\)

\(=42+258+2\)

\(=300+2\)

\(=302\)

14 x 14 + 2 x 14 x 86 + 86 x 86 

= 14 x 14 + 14 x 86 + 14 x 86 + 86 x 86 

= 14 x ( 14 + 86 ) + 86 x ( 14 + 86 ) 

= 14 x 100 + 86 x 100 

= 100 x ( 14 + 86 ) 

= 100 x 100 

= 10000 

a) 86*(121-120+9)==86*10=860

b)136*(75+19+6)=136*100=13600

Mk giải r đó nha chắc chắn đúng

chao ban! Day la cau tra loi cua mh!

a,86*121-86*120+86*9

=86*(121-120+9)

=86*10

=860

b,136*75+136*19+136*6

=136*(75+19+6)

=136*100

=13600

Chuc ban hoc tot!!!

a)86 x (121-120+9)=860

b)136 x (75+19+6)=13600

ĐKXĐ:\(\left\{{}\begin{matrix}x\ne0\\x\ne-3\end{matrix}\right.\)

\(\dfrac{80}{x}-\dfrac{80}{x+3}=\dfrac{3}{20}\\ \Leftrightarrow80\left(\dfrac{1}{x}-\dfrac{1}{x+3}\right)=\dfrac{3}{20}\\ \Leftrightarrow\dfrac{x+3-x}{x\left(x+3\right)}=\dfrac{3}{1600}\\ \Leftrightarrow\dfrac{3}{x^2+3x}=\dfrac{3}{1600}\\ \Leftrightarrow3x^2+9x=4800\\ \Leftrightarrow x^2+3x-1600=0\\\)

Nghiệm xấu lắm bạn