\(6^{2.x+5}=216\)

\(=>6^{2.x+5}=6^3\)

=>2.x+5=3

=>2.x=3-5

=>2.x=-2

=>x=-2:2

=>x=-1

`6^(2x+5)=216`

`=> 6^(2x+5)=6^3`

`=>2x+5=3`

`=>2x=3-5`

`=>2x=-2`

`=>x=-2:2`

`=>x=-1`

`6^(2x+5)=216`

`6^(2x+5)=6^3`

`2x+5=3`

`2x=3-5`

`2x=-2`

`x=-2:2`

`x=-1`

1/4×2/6×3/8×4/10×...×14/30×15/32=1/2^x

<=>1/(2×2)×2/(2×3)×...×14/(2×15)×15/2^5=1/2^x

<=>1/2×1/2×...×1/2×1/(2^5)=1/2^x

<=>1/2^19=1/2^x=>x=19

Đề mình không ghi lại nhé.

^{\(\Rightarrow\frac{1\times2\times3\times4\times...\times14\times15}{4\times6\times10\times...\times30\times32}=\frac{1}{2^x}\)}\(\frac{1}{2^x}\)

\(\Rightarrow\frac{1\times2\times3\times4\times...\times14\times15}{2\times4\times6\times8\times10\times...\times30\times32}\)\(=\frac{1}{2^{x+1}}\)

\(\Rightarrow\frac{1}{2^{15}\times32}=\)\(\frac{1}{2^{x+1}}\)

\(\Rightarrow2^{15}\times2^5=2^{x+1}\)

\(\Rightarrow2^{20}=2^{x+1}\)

\(\Rightarrow x+1=20\Rightarrow x=19\)

Vậy \(x=1\)

Học tốt nhaaa!

Vậy x = 19 nha cậu ơi! Lỗi kỹ thuật xíu!

\(\frac{2x-10}{6}=\frac{-27}{5-x}\)

\(\frac{2\left(x-5\right)}{6}=\frac{27}{x-5}\)

\(2\left(x-5\right)^2=27\times6\)

\(2x^2-20x+50-162=0\)

\(2x^2-20x-112=0\)

\(x^2-10x-56=0\)

\(x^2-14x+4x-56=0\)

\(\left(x-14\right)\left(x+4\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-14=0\\x+4=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=14\\x=-4\end{cases}}\)

KL .....

XIN TIICK

bạn đã kiểm tra kĩ chưa vậy?mình đọc đề câu B mà loạn não luôn á;-;

mik kiểm tra rùi

\(a,\dfrac{x}{7}=\dfrac{6}{12}\\ x\cdot12=7\cdot6=42\\ x=42:12\\ x=\dfrac{7}{2}\\ b,\dfrac{-5}{x}=\dfrac{20}{28}\\ x\cdot20=\left(-5\right)\cdot28=-140\\ x=\left(-140\right):20\\ x=-7\\ c,\dfrac{x-2}{8}=\dfrac{3}{4}\\ \left(x-2\right)4=8\cdot3=24\\ x-2=24:4\\ x-2=6\\ x=6+2\\ x=8\\ d,\dfrac{x}{-5}=\dfrac{-5}{x}\\ x^2=\left(-5\right)\cdot\left(-5\right)=25\\ x=5\)

A. x = 2

B. \(\dfrac{3}{8}=\dfrac{6}{x}\)\(\Leftrightarrow x=\dfrac{6.8}{3}=16\)

C. x = 3

D. \(x=\dfrac{4.6}{8}=3\)

E. \(x=\dfrac{7}{3}\)

G.\(\dfrac{14}{13}=\dfrac{28}{10-x}\)

<=>\(14\left(10-x\right)=364\)

<=> 10 - x = 26 

<=> x = -16 

H. \(3\left(x+2\right)=4\left(x-5\right)\)

<=> 3x + 6  = 4x - 20 

<=> -x = -26

<=> x = 26

K. \(\dfrac{x}{2}=\dfrac{8}{x}\)

<=> \(x^2=16\)

<=> \(\left[{}\begin{matrix}x=4\\x=-4\end{matrix}\right.\)

M. \(\left(x-2\right)^2=100\)

<=> \(\left[{}\begin{matrix}x-2=10\\x-2=-10\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=12\\x=-8\end{matrix}\right.\)

a=2

b=16

c=3

d=3

mik chỉ biết thế này thôi(ko chắc đúng=3)

A, \(\dfrac{x}{5}=\dfrac{2}{5}\Rightarrow x=2\)

B,\(\dfrac{3}{8}=\dfrac{6}{x};\dfrac{3}{8}=\dfrac{3\cdot2}{8\cdot2}=\dfrac{6}{16}\Rightarrow x=16\)

C,\(\dfrac{1}{9}=\dfrac{x}{27};\dfrac{1}{9}=\dfrac{1\cdot3}{9\cdot3}=\dfrac{3}{27}\Rightarrow x=3\)

D,\(\dfrac{4}{x}=\dfrac{8}{6};\dfrac{4}{x}=\dfrac{4\cdot2}{x\cdot2}=\dfrac{8}{2x}\)

   \(\Rightarrow2x=6;6=x:2;x=3\)

419 bn nha 

= 419^^

         HT

lớp 6 ai chơi được

\(\left(x-2\right)^8=\left(x-2\right)^6\)

\(\Leftrightarrow\left(x-2\right)^8-\left(x-2\right)^6=0\)

\(\Leftrightarrow\left(x-2\right)^6\left[\left(x-2\right)^2-1\right]=0\)

\(\Leftrightarrow\left(x-2\right)^6\left(x-3\right)\left(x-1\right)=0\)

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

=>x-2=0 hoặc x-2=1

=>x-2=0=>x=2

=>x-2=1=>x=3

\(\left(x-2\right)^8=\left(x-2\right)^6\)

\(\left(x-2\right)^8-\left(x-2\right)^6=0\)

\(\left(x-2\right)^6.\left[\left(x-2\right)^2-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}\left(x-2\right)^6=0\\\left(x-2\right)^2-1=0\end{cases}\Rightarrow\orbr{\begin{cases}x-2=0\\\left(x-2\right)^2=1\end{cases}\Rightarrow}\orbr{\begin{cases}x=2\\x-2=1\end{cases}\Rightarrow}\orbr{\begin{cases}x=2\\x=3\end{cases}}}\)