6x=5^21 chia 5^19+14-1

6x=25+12-1

6x=36 suy ra x=6

\(\text{7x - x = 5}^{21}:5^{19}+3.2^2-7^0\)

\(\text{(7-1)x=5}^2\text{ + 3. 4 - 1}\)

\(\text{6x = 25 + 12 - 1}\)

\(\text{6x = 36}\)

\(\text{ x = 6}\)

a)7.x-x=5²¹ :5¹⁹ +3.2² -7⁰

  x.(7-1)=5²+12-1

  x.6     =36

  x         =36:6=6

b)7.x-2.x=6¹⁷:6¹⁵+44:11

   x.(7-2)=6²+4

  x.5      =40

 x=40:5=8

may cai bai day ma cung khong biet oc cho

a) 89-(73-x)=20

=>73-x=89-20

=>73-x=69

=>x=73-69

=>x=4

7x-10=2 mũ 2

7x-10=4

7x=14

x=2

7x - 10 = 2⁷ : 2⁵

=> 7x - 10 = 2²

=> 7x - 10 = 4

=> 7x = 14

=> x = 2

\(\Rightarrow\left(7x-11\right)^3=\left(2\cdot5\right)^5+200=10^5+200\\ \Rightarrow\left(7x-11\right)^3=10000+200=10200\\ \Rightarrow7x-11=\sqrt[3]{10200}\\ \Rightarrow x=\dfrac{\sqrt[3]{10200}+11}{7}\)

a=197

b=157

c=121

d=16400

a)197

b)157

c)121

d)16400

25/7nha

 Bài 1:

1; 5\(x\) + \(x\) = 39 - 3¹¹ : 3⁹

    \(x\).(5 + 1) = 39 - 3²

    \(x.6\)        = 39 - 9

   \(x.6\)         = 30

   \(x\)           = 30 : 6

   \(x\)          = 5

Vậy \(x\) = 5

2; 5\(x\) + \(x\) = 150 : 2 + 3

    \(x\).(5 + 1) = 75 + 3

    \(x.6\)          = 78

    \(x\)             = 78 : 6

     \(x\)            = 13

Vậy \(x=13\) 

1: Ta có: \(\left(7x-3^2\right):5=8\)

\(\Leftrightarrow7x-9=40\)

hay x=7