x .9 = − 27 ⇔ x = − 3

x= -24 

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         x + 1/27 = x/9

<=>  27x+1/27 = 3x/27

 <=> 27x+1 = 3x

  <=> 27x-3x= - 1

<=> 24x= -1

<=> x = -1/24

a)  x + 27 = 9 ⇔ x = 9 − 27 ⇔ x = − 18

b)  x – 35 = 15 ⇔ x = 15 + 35 ⇔ x = 50.

c)  − 13 −   x = 39 ⇔ −   x = 39 + 13 ⇔ − x = 52 ⇔ x = − 52.

3x + 27 = 9

        3x = 9 - 27

         3x = -18

           x = -18 : 3

           x = -6

Vậy x = -6

3x+27=9 \(\Rightarrow\)3x=-18\(\Rightarrow\)x=-6

Answer:

\(9.\left(x+28\right)=0\)

\(\Rightarrow x+28=0\)

\(\Rightarrow x=-28\)

\(\left(27-x\right).\left(x+9\right)=0\)

\(\Rightarrow\orbr{\begin{cases}27-x=0\\x+9=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=27\\x=-9\end{cases}}\)

\(\left(-x\right).\left(x-43\right)=0\)

\(\Rightarrow\orbr{\begin{cases}-x=0\\x-43=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=0\\x=43\end{cases}}\)

a) 9 . ( x + 28 ) = 0 <=> x = -28

b) (27-x)(x+9)= 0 <=> x = 27 hoac x = -9

c) (-x)(x-43)=0 <=> x =0 hoac x = 43

a, => (-3).(-x) = -9

=> 3x=-9

=> x=-9:3=-3

b, => -3^x = -3^3

=> x=3

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