Question

1. so sánh

a, 17^15 và 31^10 

b, 625^5 và 125^7

c, 8^29 và 16^22

d, 27^50 và 81^38

e, 625^55 và 125^ 73

2. tìm x thuộc N, biết:

a, (x - 15) . 15 = 0

b, 32. (x - 10)= 32

c, 12.3 + 12.x = 0

d, 5.4 +5. x = 0

e, 11. 3 + 6. x=0

f, 9.27 + x. 3= 0

giúp mik với, mik đang cần gấp!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

`a) 31^10 < 36^10 = 6^20 = 2^20 . 3^20 = 2^20 . 9^10`

`17^15 > 16^15 = 4^30 = 2^60 = 2^20 . 16^10`

Do `9^10 < 16^10`

`=> 31^10 < 17^15 `

Vậy ....

`b) 625^5 = (5^4)^5 = 5^20`

`125^7 = (5^3)^7 = 5^21`

Do `5^20 < 5^21 ```

`=> 625^5  < 125^7`

Vậy ....

`c) 8^29 = (2^3)^29 = 2^87`

`16^22 = (2^4)^22 = 2^88`

Do `2^87 < 2^88`

`=> 8^29 < 16^22`

Vậy ....

`d) 27^50 = (3^3)^50 = 3^150`

`81^38 = (3^4)^38 = 3^152`

Do `3^150 < 3^152`

`=> 27^50 < 81^38`

Vậy ....``

`e) 625^55 = (5^4)^55 = 5^220`

`125^73 = (5^3)^73 = 5^219`

Do `5^220 > 5^219`

`=> 625^55 > 125^73`

Vậy ...

Answer 2

2. 
a, \(\left(x-15\right).15=0\)
\(\Rightarrow x-15=0\)
\(\Rightarrow x=0+15\)
\(\Rightarrow x=15\)
b, \(32.\left(x-10\right)=32\)
\(\Rightarrow x-10=32:32\)
\(\Rightarrow x-10=1\)
\(\Rightarrow x=1+10\)
\(\Rightarrow x=11\)
c, \(12.3+12.x=0\)
\(\Rightarrow12.\left(3+x\right)=0\)
\(\Rightarrow3+x=0\)
\(\Rightarrow x=0-3\)
\(\Rightarrow x=-3\left(l\right)\)
\(\Rightarrow x\) ∈ ∅
d, \(5.4+5.x=0\)
\(\Rightarrow5.\left(4+x\right)=0\)
\(\Rightarrow\text{4+x=0}\)
\(\Rightarrow x=0-4\)
\(\Rightarrow x=-4\left(l\right)\)
\(\Rightarrow x\) ∈ ∅
e, \(11.3+6.x=0\)
\(\Rightarrow11.3+3.2x=0\)
\(\Rightarrow3.\left(11+2x\right)=0\)
\(\Rightarrow11+2x=0\)
\(\Rightarrow2x=-11\)
\(\Rightarrow x=-\dfrac{11}{2}\left(l\right)\)
\(\Rightarrow x\) ϵ ∅
f, \(9.27+x.3=0\)
\(\Rightarrow3^5+x.3=0\)
\(\Rightarrow3.\left(3^4+x\right)=0\)
\(\Rightarrow3^4+x=0\)
\(\Rightarrow x=-3^4\left(l\right)\)
\(\Rightarrow x\) ∈ ∅