a) 89-(73-x)=20

=>73-x=89-20

=>73-x=69

=>x=73-69

=>x=4

A . 89 - ( 73 - x ) = 20

              73 - x   = 89 - 20

              73 - x   = 69

              \(\Rightarrow\)x = 4

B .

chịu

Chịu 

(1-2x)* 0.13 = 0.07 (lay xap xi do nha ban )

1-2x = 0.07 /0.13 

1-2x = \(\frac{7}{13}\)

2x = \(\frac{7}{13}\)- 1

2x= \(\frac{-6}{13}\)

x= \(\frac{-6}{13}\) / 2

x= -3 phần 13 

\(\left(1-2x\right)\cdot\left(\frac{3}{4}\right)^7=\left(\frac{3}{4}\right)^9\)

\(\left(1-2x\right)=\left(\frac{3}{4}\right)^9:\left(\frac{3}{4}\right)^7\)

\(1-2x=\left(\frac{3}{4}\right)^2\)

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

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

\(2x=\frac{7}{16}\)

\(x=\frac{7}{16}:2\)

\(x=\frac{7}{16}\cdot\frac{1}{2}\)

\(x=\frac{7}{32}\)

a. x = {3;-3}

b. x thuộc rỗng

c. x²-4=0

    x²  = 4

    x={2;-2}

d. x²+1=82

    x²   =83

 x thuộc rỗng

e. (2x)²=6

    x thuộc rỗng

f. (x-1)²=9

  TH1: x-1=3=>x=4

  TH2: x-1=-3=>x=-2

Vậy x={4;-2}

g.(2x+3)²=25

  TH1: 2x+3=5=> x=1

  Th2: 2x+3=-5=>x=-4

VẬY X={1;-4}

a, x^2= 9 

=>\(\sqrt{9}=3\)

b,\(x^2=5=>x=\sqrt{5}\)

c, x^2-4=0

=>x^2=4

=>x=2

d, x^2+1=82

=>x^2=81 =>\(\sqrt{81}=9\)

3, 2x^2=6

=>x= \(\sqrt{6}\)

f, {x-1} ^2=9

=> x-1=3

=>x=2

g{ 2x+3}^2=25

=> 2x+3=5

=>2x=2

=>x=1

  Bài 1:

2^\(x\) = 4

2\(^x\) = 2²

 \(x=2\)

Vậy \(x=2\)

Bài 2:

2\(^x\) = 8

2\(^x\) = 2³

\(x=3\)

Vậy \(x=3\)

a. x mũ 2 - 2x + 1 = 25 

= x^2 + 2.x.1 + 1^2

= ( x + 1 ) ^2

ko bt có đúng ko nữa, mấy câu kia tui ko bt lm

Sos

a) \(4^n=4096\Rightarrow4^n=4^6\Rightarrow n=6\)

b) \(5^n=15625\Rightarrow5^n=5^6\Rightarrow n=6\)

c) \(6^{n+3}=216\Rightarrow6^{n+3}=6^3\Rightarrow n+3=3\Rightarrow n=0\)

d) \(x^2=x^3\Rightarrow x^3-x^2=0\Rightarrow x^2\left(x-1\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x-1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)

e) \(3^{x-1}=27\Rightarrow3^{x-1}=3^3\Rightarrow x-1=3\Rightarrow x=4\)

f) \(3^{x+1}=9\Rightarrow3^{x+1}=3^2\Rightarrow x+1=2\Rightarrow x=1\)

g) \(6^{x+1}=36\Rightarrow6^{x+1}=6^2\Rightarrow x+1=2\Rightarrow x=1\)

h) \(3^{2x+1}=27\Rightarrow3^{2x+1}=3^3\Rightarrow2x+1=3\Rightarrow2x=2\Rightarrow x=1\)

i) \(x^{50}=x\Rightarrow x^{50}-x=0\Rightarrow x\left(x^{49}-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}-1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}=1=1^{49}\end{matrix}\right.\)  \(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)

4ⁿ  =  4096 

4ⁿ = 2¹²

n = 12

5ⁿ = 15625 

5ⁿ = 5⁶

n   = 6

6ⁿ⁺³ = 216

6ⁿ⁺³ = 2³.3³

6ⁿ⁺³ = 6³

n + 3 = 3