\(\left(26-3x\right):5+71=75\)

\(\left(26-3x\right):5=4\)

\(26-3x=20\)

\(3x=6\)

\(x=2\)

\(5^{x+1}=125\)

\(5^{x-1}=5^3\)

\(\Rightarrow x-1=3\)

\(\Rightarrow x=4\)

\(\left(26-3x\right):5+71=75\)

\(\Rightarrow\left(26-3x\right)=\left(75-71\right).5\)

\(\Rightarrow26-3x=20\)

\(\Rightarrow x=2\)

\(\left(26-3x\right):5+71=75\)

\(\left(26-3x\right):5=4\)

\(26-3x=20\)

\(3x=6\)

\(x=2\)

\(5^{x+1}=125\)

\(5^{x-1}=5^3\)

\(\Rightarrow x-1=3\)

\(\Rightarrow x=4\)

Lời giải:
a.

$(x-15).27=0$

$x-15=0:27=0$

$x=15+0=15$

b.

$23(42-x)=0$

$42-x=0$

$x=42$

c.

$(9x+2).3=60$

$9x+2=60:3=20$

$9x=18$

$x=2$
d.

$71+(26-3x):5=75$

$(26-3x):5=75-71=4$

$26-3x=4.5=20$

$3x=26-20=6$

$x=6:2=3$

d) 71 + (26 – 3x) : 5 = 75

(26 – 3x) : 5 = 75 – 71

(26 – 3x) : 5 = 4

26 – 3x = 4 . 5

26 – 3x = 20

3x = 26 – 20

3x = 6

x = 6 : 3 = 2

Vậy x = 2

( 26 - 3x ) : 5 = 75 - 71

( 26 - 3x ) : 5 = 4

26 - 3x = 4 x 5

26 - 3x = 20

3x = 26 - 20

3x = 6

x = 6 : 3

x = 2

71 + (26-3x) :5 = 75

=> (26-3x):5 = 75-71

=> (26-3x) : 5 = 4

=> 26-3x=4.5

=> 26-3x=20

=> 3x=26-20

=> 3x=6

=> x=6:3

=> x=2

x = 2 nha bn

k giùm mk nha các bn

>_< học tốt

\(\left(26-3x\right):5+71=75\)

\(\left(26-3x\right):5=4\)

\(26-3x=20\)

\(3x=6\)

\(x=2\)

(26-3x):5+71=75

(26-3x):5=4

26-3x=20

3x=6

x=2

câu 1 : ( 26 - 3x ) : 5 + 71 = 75

              ( 26 - 3x ) : 5 = 4

                 26 - 3x =20

                  3x = 26 - 20

                    3x=6

                      x=6: 3

                      x=2

C4: 100 - 7( 5 - x) = 58

      7( 5 -x ) = 100- 58

       7( 5 - x) =42

          5 - x = 42 : 7

          5 - x = 6

               x = -1 

1. \(\left(26-3x\right):5+71=75\)

\(\left(26-3x\right):=75-71\)

\(\left(26-3x\right):5=4\)

\(26-3x=4.5\)

\(26-3x=20\)

\(3x=26-20\)

\(3x=6\)

\(x=6:3\)

\(x=2\)

2. \(5^{x+1}=125=5^3\) 

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

3. B = {x​​ ϵ N/30 < x < 40}

B = {31;32;33;34;35;36;37;38;39;40}

4. \(100-7\left(5-x\right)=58\)

\(100-35+7x=58\)

\(-7x=100-35-58=7\)

\(x=-7:7\)

\(x=-1\)

\(\left(26-3x\right):5+71=75\\ \Leftrightarrow\left(26-3x\right):5=4\\ \Leftrightarrow26-3x=20\\ \Leftrightarrow3x=6\\ \Leftrightarrow x=2\)

Vậy x = 2

(26-3x):5=75-71

(26-3x):5=4

(26-3x)=4.5

(26-3x)=20

3x       =26-20

3x       =6

x         =6:3

x         =2

<=> (26-3x):5=4

<=> 26-3x=20

<=> 3x=6

<=> x=2

vậy x=2

đc đấy 

nhưng tôi làm xong tc rùi

x = 2 nha , k

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