
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.



\(139,\)
a)Ta có
\(56=2^3.7\)
\(140=2^2.5.7\)
\(\Rightarrow UCLN\left(56,140\right)=2^2.7=28\)
b) Ta có :
\(24=2^3.3\)
\(84=2^2.3.7\)
\(180=2^2.5.3^2\)
\(\Rightarrow UCLN\left(24,84,180\right)=2^2.3=12\)
c)Ta có
\(60=2^2.3.5\)
\(180=2^2.5.3^2\)
\(\Rightarrow UCLN\left(60,180\right)=2^2.3.5=60\)
d) Ta có :
\(15=3.5\)
\(19=19\)
\(\Rightarrow UCLN\left(15,19\right)=1\)
#Rảnh
\(140,\)
a) Ta có :
\(16=2^4\)
\(80=2^4.5\)
\(176=2^4.11\)
\(\Rightarrow UCLN\left(16,80,176\right)=2^4=16\)
b) Ta có:
\(18=2.3^2\)
\(30=2.3.5\)
\(77=7.11\)
\(\Rightarrow UCLN\left(18,30,77\right)=2.3=6\)
#Rảnh


Câu 8:
a:Sửa đề: \(4+4^2+\cdots+4^{2025}\)
Ta có: \(4+4^2+\cdots+4^{2025}\)
\(=\left(4+4^2+4^3\right)+\left(4^4+4^5+4^6\right)+\cdots+\left(4^{2023}+4^{2024}+4^{2025}\right)\)
\(=4\left(1+4+4^2\right)+4^4\left(1+4+4^2\right)+\cdots+4^{2023}\left(1+4+4^2\right)\)
\(=21\left(4+4^4+\cdots+4^{2023}\right)\) ⋮21
b: \(5+5^2+5^3+5^4+\cdots+5^{2024}\)
\(=\left(5+5^2\right)+\left(5^3+5^4\right)+\cdots+\left(5^{2023}+5^{2024}\right)\)
\(=\left(5+5^2\right)+5^2\left(5+5^2\right)+\cdots+5^{2022}\left(5+5^2\right)\)
\(=30\left(1+5^2+\cdots+5^{2022}\right)\) ⋮30
Câu 7:
a: \(A=2+2^2+2^3+\cdots+2^{99}\)
=>\(2A=2^2+2^3+\cdots+2^{100}\)
=>\(2A-A=2^2+2^3+\cdots+2^{100}-2-2^2-\cdots-2^{99}\)
=>\(A=2^{100}-2\)
b: \(B=1-7+7^2-7^3+\cdots+7^{48}-7^{49}\)
=>\(7B=7-7^2+7^3-7^4+\cdots+7^{49}-7^{50}\)
=>\(7B+B=7-7^2+7^3-7^4+\cdots+7^{49}-7^{50}+1-7+7^2-7^3+\cdots+7^{48}-7^{49}\)
=>\(8B=-7^{50}+1\)
=>\(B=\frac{-7^{50}+1}{8}\)
Câu 4:
a: \(x^3=125\)
=>\(x^3=5^3\)
=>x=5
b: \(11^{x+1}=121\)
=>\(11^{x+1}=11^2\)
=>x+1=2
=>x=2-1=1
c: \(\left(x-5\right)^3=27\)
=>\(\left(x-5\right)^3=3^3\)
=>x-5=3
=>x=3+5=8
d: \(4^5:4^{x}=16\)
=>\(4^{x}=4^5:16=4^5:4^2=4^3\)
=>x=3
e: \(5^{x-1}\cdot8=1000\)
=>\(5^{x-1}=1000:8=125=5^3\)
=>x-1=3
=>x=3+1=4
f: \(2^{x}+2^{x+3}=72\)
=>\(2^{x}+2^{x}\cdot8=72\)
=>\(2^{x}\cdot9=72\)
=>\(2^{x}=\frac{72}{9}=8=2^3\)
=>x=3
g: \(\left(3x+1\right)^3=343\)
=>\(\left(3x+1\right)^3=7^3\)
=>3x+1=7
=>3x=6
=>x=2
h: \(3^{x}+3^{x+2}=270\)
=>\(3^{x}+3^{x}\cdot9=270\)
=>\(10\cdot3^{x}=270\)
=>\(3^{x}=\frac{270}{10}=27=3^3\)
=>x=3
i: \(25^{2x+4}=125^{x+3}\)
=>\(\left(5^2\right)^{2x+4}=\left(5^3\right)^{x+3}\)
=>\(5^{4x+8}=5^{3x+9}\)
=>4x+8=3x+9
=>x=1
Câu 6:
1 giờ=3600 giây
Số tế bào hồng cầu được tạo ra sau mỗi giờ là:
\(25\cdot10^5\cdot3600=25\cdot36\cdot10^7=900\cdot10^7=9\cdot10^9\) =9 tỉ (tế bào)
câu 5:
a. \(16^{16}=\left(2^4\right)^{16}=2^{64}\)
\(64^{11}=\left(2^6\right)^{11}=2^{66}\)
vì \(2^{66}>2^{64}\) nên \(64^{11}>16^{16}\)
b. \(625^5=\left(5^4\right)^5=5^{20}\)
\(125^7=\left(5^3\right)^7=5^{21}\)
\(5^{20}<5^{21}\Rightarrow625^5<125^7\)
c. \(3^{36}=\left(3^3\right)^{12}=27^{12}\)
\(5^{24}=\left(5^2\right)^{12}=25^{12}\)
\(27^{12}>25^{12}\Rightarrow3^{36}>5^{24}\)

a)x2=4 d)6x3-8=40 g)(x-1)3=27 b)x2=25 c)3x5-1=2
\(\Rightarrow\)x=2 6x3 =40+8=48 (x-1)3=\(\pm\)(3)3 \(\Rightarrow\)x=5 3x5 =2+1=3
x3 =48:6=8 Vậy x-1=3 hoặc x-1=-3 x5 3:3=1
\(\Rightarrow\)x=2 x =3+1 x =(-3)+1 \(\Rightarrow\)x=1
x =4 x =-2
\(\Rightarrow\)x\(\in\)+{4;(-2)}
e)(x-2)2=4 f)(x+1)2=25 h)(x+1)3=64
(x-2)2=\(\pm\)(2)2 (x+1)2=\(\pm\)(5)2 (x+1)3=\(\pm\)(4)3
Vậy x-2=2 hoặc x-2=(-2) Vậy x+1=5 hoặc x+1=-5 Vậy x+1=4 hoặc x+1=-4
x =2+2 x =(-2)+2 x =5+1 x =(-5)+1 x =4+1 x =(-4)+1
x =4 x =0 x =6 x =-4 x =5 x =-3
\(\Rightarrow\)x\(\in\){4;0} \(\Rightarrow\)x\(\in\){6;(-4)} \(\Rightarrow\)x\(\in\){5;(-3)}
Hok tốt!

a) Để \(\frac{7}{n+1}\) đạt giá trị nguyên
<=> 7 \(⋮\) ( n + 1 )
=> n + 1 \(\in\) Ư(7) = { - 7 ; -1 ; 1 ; 7 }
=> n \(\in\) { -8 ; -2 ; 0 ; 6 }
b) Để \(\frac{n+5}{n-2}\) đạt giá trị nguyên
<=> \(n+5⋮n-2\)
=> ( n - 2 ) + 7 \(⋮\) n - 2
=> 7 \(⋮\) n - 2
=> n - 2 \(\in\) Ư(7) = { - 7 ; - 1 ; 1 ; 7 }
=> n \(\in\) { - 5 ; 1 ; 3 ; 9 }
c) Để \(\frac{4n-1}{n-3}\) đạt giá trị nguyên
<=> 4n-1 \(⋮\) n - 3
=> ( 4n - 12 ) + 11 \(⋮\) n- 3
=> 4(n-3) + 11 \(⋮\) n - 3
=> 11 \(⋮\)n - 3
=> n - 3 \(\in\) Ư(11) = { - 11 ; - 1 ; 1 ; 11}
=> n \(\in\) { - 8 ; 2 ; 4 ; 14 }



a) Ư(60):{ 1;2;3;4;5;6;10;12;15;20;30;60}
Ư(84):{ 1;2;4;6;7;12;14;21;42;84}
Ư(120):{ 1;2;3;4;5;6;8;10;12;15;20;24;30;40;60;120}
ƯC(60;84;120):{ 2;4;6;12}
nhưng vì x_> 6 nên x = 2,4,6