bạn ghi sai đề thì phải

đề có sai ko thế em 

d) \(\left(7-2x\right)^2=49\)

\(\Rightarrow\left(7-2x\right)^2=\left(\pm7\right)^2\)

\(\Rightarrow\left[{}\begin{matrix}7-2x=7\\7-2x=-7\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=7-7\\2x=7+7\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=0\\2x=14\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x=7\end{matrix}\right.\)

e) \(\left(9-x\right)^3=216\)

\(\Rightarrow\left(9-x\right)^3=6^3\)

\(\Rightarrow9-x=6\)

\(\Rightarrow x=9-6\)

\(\Rightarrow x=3\)

g) \(6^{x+2}+6^x=1332\)

\(\Rightarrow6^x\cdot\left(6^2+1\right)=1332\)

\(\Rightarrow6^x\cdot37=1332\)

\(\Rightarrow6^x=1332:37\)

\(\Rightarrow6^x=36\)

\(\Rightarrow6^x=6^2\)

\(\Rightarrow x=2\)

\(d,\left(7-2x\right)^2=49\)

\(\Leftrightarrow\left[{}\begin{matrix}7-2x=7\\7-2x=-7\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}2x=0\\2x=14\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=7\end{matrix}\right.\)

\(e,\left(9-x\right)^3=216\)

\(\Leftrightarrow\left(9-x\right)^3=6^3\)

\(\Leftrightarrow9-x=6\)

\(\Leftrightarrow x=3\)

\(f,6^{x+2}+6^x=1332\)

\(\Leftrightarrow6^x\left(6^2+1\right)=1332\)

\(\Leftrightarrow6^x\cdot37=1332\)

\(\Leftrightarrow6^x=36\)

\(\Leftrightarrow6^x=6^2\)

\(\Leftrightarrow x=2\)

#Urushi

a) x³ = 216

216 = 6³

=> x = 6

b) x³ = x²

Tách ra, ta có : x³ = x . x . x ; x² = x . x

Chia đi ta được kết quả là x

=> x = 1

Sai thì bỏ qua -_-

a) x³  =  216

x³     =  6³

=> x  = 6

393-(126+3X)=0

        126+3X.  =393-0

          126+3X =393

                   3X =393-126

                   3X =267

                   X.   =267 : 3

                  X.     =89

Còn câu dưới hình như đề sai

chắc cô mình cho sai đề ùi....

\(25\div x=x\Leftrightarrow25=x.x\Leftrightarrow25=x^2\)

\(\Leftrightarrow\orbr{\begin{cases}x=-5\\x=5\end{cases}}\)

\(3358\div23=2x-6\)

\(\Leftrightarrow146=2x-6\)

\(\Leftrightarrow2x=152\Leftrightarrow x=76\)

\(2782\div\left[216-\left(x-3\right)\right]=13\)

\(\Leftrightarrow216-\left(x-3\right)=214\)

\(\Leftrightarrow x-3=2\)

\(\Leftrightarrow x=5\)

25:x=x=>x²=25=>x=5

3358:23=2x-6=>2x-6=146=>2x=152=>x=76

2782:[216-(x-3)=13

=>2782:13=216-(x-3)

=>214      =216-(x-3)

=>216-214= x-3

=>x-3 =2

=>x=5

Tk nha, thanks nhìu ^_^

a) x = 12  

b) x= 27              

c) x = 3 

d) x = 2

a) 71 - (33 + x) = 26
             33 + x  = 71 - 26
             33 + x  = 45
                     x  = 45 - 33
                     x  =     12

( x-6)^2 = 9

(x-6)^2=3^2

=>x-6=3

   x=3+6

  x=9

(2x-7)^2= 169 

(2x-7)^2=13^2

=>2x-7=13

  2x=13+7

  2x=20

   x=10:2

   x=10

x^3 = 216 

x^3=6^3

=>x=6

(x-6)^2=9

x-6^2=9

x-36=9

x=9+36

x=45

(2x-7)^2=169

2x-7^2=169

2x-49=169

2x=169+49

2x=218

x=218:2

x=109

x^3=216

x^3=6^3

=>x=6

tick cho mk nha bạn