\(2^n+2^{n+3}=144\)
\(\Rightarrow2^n\left(1+2^3\right)=144\)
\(\Rightarrow2^n\cdot9=144\)
\(\Rightarrow2^n\cdot9=144\)
\(\Rightarrow2^n=16=2^4\)
\(\Rightarrow n=4\)
1. Tìm a,b,c biết:
a) a/b = 8/5; b/c = 2/7 và a+b+c= 61
b) ab = 1/2; bc= 2/3; ac = 3/4
c) 3a=2b; 5b = 7c và 3a + 5c - 7b= 60
2. tìm các số nguyên n sao cho:
1) 5^n + 5^n+2 = 650
2) 32^-n .16^n = 1024
3) 3^-1 .3^n+ 5. 3^n-1 = 162
4) 125. 5\(\ge\)5^n\(\ge\)5 . 25
5) (n^54)^2 = n
6) 243\(\ge\)3^n\(\ge\)9.27
7) 2^n+3 . 2^n = 144
8)3<3^n\(\le\)234
9) 8. 16\(\ge\)2^n\(\ge\)4
10) 4^15. 9^15<2^n.3^n< 18^16. 2^16
11) 4^11. 25^11\(\le\)2^n. 5^n\(\le\)20^12. 5^12
12)\(\frac{4^5+4^5+4^5+4^5}{3^5+3^5+3^5}\).\(\frac{6^5+6^5+6^5+6^5+6^5+6^5}{2^5+2^5}\)= 2^n
13) 9. 27^n= 3^5
14) (2^3 : 4) . 2^n= 4
15) 3^-2 . 3^4. 3^n = 3^7
16)2^-1. 2^n +4.2^n=9.2^5
tim x
2x+2x+3=144
tìm x ;
1. -5x - 9 = 5 - x
2. 2\(^{\left(x-5\right)}\) \(^{\left(x+2\right)}\) = 1
3. 2\(^x\) + 2 \(^{x+3}\) = 144
chứng minh
a) 3^n+2 - 2^n+2 + 3^n - 2^n chia hết cho 10
b) 3^n+3 + 3^n+1 + 2^n+3 + 2^n+2 chia hết cho 6
Thực hiện phép tính (tính nhanh nếu có thể):
a) \(\left(\dfrac{1}{2}-\dfrac{1}{3}\right)-\left(\dfrac{5}{3}-\dfrac{3}{2}\right)+\left(\dfrac{7}{3}-\dfrac{5}{2}\right)\)
b) \(\left(\dfrac{3}{4}-1\dfrac{1}{6}\right)^2:\sqrt{\dfrac{25}{144}}\)
1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+...+1/n+2/n+3/n+...+n-1/n
Chứng minh:\(3^{n+3}+3^{n+1}+2^{n+3}+2^{n+2}⋮6\)
Chứng minh: \(3^{n+2}-2^{n+2}+3^n-2^n⋮10\)
Chứng minh rằng với mỗi số nguyên dương n thì:
\(3^{n+3}+3^{n+1}+2^{n+3}+2^{n+2}⋮6\)
