1) 5x+2x =6²-5⁰

5x+2x = 35

7x      = 35

x= 35:7

x = 5

2)

7x-x=5²¹:5¹⁹+3 . 2²-7⁰

7x-x = 25+11

6x = 36

x = 36:6

x=6

Đúng nha !!!!

a) 5x  + 2x = 6² - 5⁰

x ( 5 + 2 ) = 36 - 1

x . 7 = 35

x = 35 : 7

x = 5

1) 6x+x=28 => 7x=28 => x= 28:7=4.
2) \(5x+x=39-3^{11}:3^9=>6x=39-3^2=>6x=39-9=>6x=30=>x=30:6=5\)
3) \(7x-x=5^{21}:5^{19}+3.2^2-7^0.7\)
   \(6x=5^2+3.4-1.7=>6x=25+12-7=>6x=30=>x=30:6=5.\)
4)\(7x-2x=6^{17}:6^{15}+44:11=>5x=6^2+4=>5x=36+4=>5x=40=>x=40:5=8.\)

7x-x=5²¹:5¹⁹+3.2²-7⁰

=> 6x = 5^2 + 12 -1

=> 6x = 36

=> x = 36/6 = 6

Kết quả 6

Học tốt

Câu a:

16^x < 128^4

(2^4)^x < (2^7)^4

2^4x < 2^28

4x < 28

x < 28 : 4

x < 7

Câu b:

5\(^{x}\).5\(^{x+1}\).5\(^{x+2}\) ≤ 100...0: 2\(^{18}\)

5\(^{3x+3}\) ≤ 2\(^{18}\).5\(^{18}\) : 2\(^{18}\)

5\(^{3x+3}\) ≤ 5\(^{18}\).(2\(^{18}\) : 2\(^{18}\))

5\(^{3x+3}\) ≤ 5\(^{18}\)

3\(x+3\) ≤ 18

3(\(x+1\)) ≤ 18

\(x+1\) ≤ 18 : 3

\(x+1\) ≤ 9

\(x\) ≤ 9 - 1

\(x\) ≤ 8

\(\frac{3}{5}ha+\frac{2}{7}ha=\frac{31}{35}ha\)

\(\frac{7}{8}ha-\frac{1}{2}ha=\frac{3}{8}ha\)

\(\frac{5}{8}m^2+\frac{3}{8}m^2\times2=\frac{5}{8}m^2+\frac{3}{4}m^2=\frac{11}{8}m^2\)

\(\frac{2}{7}m^2\div2+6m^2=\frac{1}{7}m^2+6=\frac{43}{7}m^2\)

5^6+5^7+5^8

=5^6.(1+5+5^2)

=5^6.31 chia hết cho 31

7^6+7^5-7^4

=7^4.(7^2+7-1)

=7^4.55 chia hết cho 11

BÀI 2:

a)  \(5^6+5^7+5^8=5^6\left(1+5+5^2\right)=5^6.31\)      \(⋮\)\(31\)

b)  \(7^6+7^5-7^4=7^4.\left(7^2+7-1\right)=7^4.55\)\(⋮\)\(11\)

c)  \(2^3+2^4+2^5=2^3.\left(1+2+2^2\right)=2^3.7\)\(⋮\)\(7\)

d) mk chỉnh đề

 \(1+2+2^2+2^3+...+2^{59}\)

\(=\left(1+2\right)+\left(2^2+2^3\right)+...+\left(2^{58}+2^{59}\right)\)

\(=\left(1+2\right)+2^2\left(1+2\right)+...+2^{58}\left(1+2\right)\)

\(=\left(1+2\right)\left(1+2^2+...+2^{58}\right)\)

\(=3\left(1+2^2+...+2^{58}\right)\)\(⋮\)\(3\)