\(\dfrac{4^5x9^4}{8^3x27^3}\)
a) rút gọn: \(\dfrac{4^5x9^4-2x6^9}{2^{10}x3^8+6^8x20}\)
b) Cho A=\(\dfrac{1}{2}+\dfrac{2}{2^2}+\dfrac{3}{2^3}+\dfrac{4}{2^4}+\dfrac{5}{2^5}+...\dfrac{99}{2^{99}}+\dfrac{100}{2^{100}}\).So sánh A với 2
a: \(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)
\(=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot2^2\cdot5}\)
\(=\dfrac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^8\cdot5}\)
\(=\dfrac{2^{10}\cdot3^8\left(1-3\right)}{2^{10}\cdot3^8\left(1+5\right)}=\dfrac{-2}{6}=-\dfrac{1}{3}\)
\(\dfrac{4}{1x5}\) \(+\) \(\dfrac{4}{5x9}\) \(+\) \(\dfrac{4}{9x13}\) \(+\) ... \(+\) \(\dfrac{4}{53x57}\)
4^6 x 8^10 =
9^3x27^4 =
16 . 3^4 =
AI NHANH THÌ TỚ TICK CHO
4^6.8^10=8^4.8^10 =8^14
9^3.27^4=9^9
16.3^4 =6^4
k mình nhé!xin mà
Tìm x:
\(\dfrac{7}{x}\)+\(\dfrac{4}{5x9}\)+\(\dfrac{4}{9x13}\)+.....+\(\dfrac{4}{41x45}\)=\(\dfrac{29}{45}\)
\(\Rightarrow\dfrac{7}{x}+\dfrac{1}{5}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{13}+...+\dfrac{1}{41}-\dfrac{1}{45}=\dfrac{29}{45}\left(x\ne0\right)\\ \Rightarrow\dfrac{7}{x}+\dfrac{1}{5}-\dfrac{1}{45}=\dfrac{29}{45}\\ \Rightarrow\dfrac{7}{x}+\dfrac{8}{45}=\dfrac{29}{45}\\ \Rightarrow\dfrac{7}{x}=\dfrac{21}{45}\Rightarrow\dfrac{21}{3x}=\dfrac{21}{45}\Rightarrow3x=45\\ \Rightarrow x=15\)
Rút gọn : A=4^5x9^4-2x6^9/ 2^10x 3^8 + 6^8 x 20
4^5x9^4 - 2x6^9 / 2^10x3^8+6^8x20
4^5x9^4-2x6^10/2^10 x3^8- 6^9x20
Tính
A=\(\dfrac{4^5x9^4-2x6^9}{2^{10}x3^8+6^8x20}\)
\(\dfrac{1}{1x2x3}+\dfrac{1}{2x3x4}+...+\dfrac{1}{2015x1016x1017}\)
CHÚ Ý: \(x\) là dấu nhân nhé.Sáng mai mk phải nộp rồi.Mong các bạn giúp mk nha!Mơn nhiều
Rút gọn biểu thức
4^5x9^4-2x6^10/2^10x3^8-6^9x20
1+2+3+4+5+6+7+8+9+10=A
5x9+5=B
(A+B):3 du ?
Ta có:A=1+2+3+4+5+6+7+8+9+10 =55
B=5x9+5=50
=>(A+B):3=(55+50):3
=105:3
=35
=>Dư 0
ta có: A = 1 + 2+3+4+5+6+7+8+9+10
A= ( 1+10) x 10 : 2
A = 55
B = 5 x 9 + 5 = 50
=> ( A+B) :3 = ( 55 +50) : 3 = 105 : 3 = 35 dư 0
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = A = 45
5 x 9 + 5 = B = 50
(A + B) : 3
(45 + 50) : 3 = 31 dư 2