\(3.8.5^2+2.4^3.12+\left(2^3+3\right).6.4\)
\(3.8.5^2+2.4^3.12+\left(2^3+3\right).6.4\)
\(600:\left\{450-\left[450-\left(2^3.5^2\right)\right]\right\}\)
Bài 1: Tính. ( Nhanh nếu có thể )
a) \(25.8^3-23.8^3\)
b) \(5^4-2.5^3\)
c) \(2.4^3-4^3.7-6.4^3\)
d) \(3^2.10^3-\left[13^2-\left(5^2.4+2^2.15\right)\right].10^3\)
a) \(25.8^3-23.8^3=8^3\left(25-23\right)\)
\(=8^3.2\)
\(=2^9.2=2^{10}\)
b) \(5^4-2.5^3=5^3.5-2.5^3\)
\(=5^3\left(5-2\right)\)
\(=5^3.3=375\)
c)\(2.4^3-4^3.7-6.4^3=4^3\left(2-7-6\right)\)
\(=4^3.-11=-704\)
d)\(3^2.10^3-\left[13^2-\left(5^2.4+2^2.15\right)\right].10^3\)
\(=3^2.10^3-\left[13^2-2^2\left(5^2+15\right)\right].10^3\)
\(=3^2.10^3-\left[13^2-2^2.40\right].10^3\)
\(=10^3\left[3^2-9\right]\)
\(=0\)
Bài 1: Tính ( Nhanh nếu có thể )
a) \(25.8^3-23.8^3\)
b) \(5^4-2.5^3\)
c) \(2.4^3-4^3.7-6.4^3\)
d) \(3^2.10^3-\left[13^2-\left(5^2.4+2^2.15\right)\right]\)
Bài 1 :
a) \(25.8^3-23.8^3\)
\(=8^3.\left(25-23\right)\)
\(=512.2=1024\)
b) \(5^4-2.5^3\)
\(=5^3.5-2.5^3\)
\(=5^3\left(5-2\right)\)
\(=125.3\)
\(=375\)
c) \(2.4^3-4^3.7-6.4^3\)
\(=4^3.\left(2-7-6\right)\)
\(=64.\left(-11\right)=-704\)
d) \(3^2.10^3-\left[13^2-\left(5^2.4+2^2.15\right)\right]\)
\(=9.1000-\left[169-\left(25.4+4.15\right)\right]\)
\(=9000-\left[169-4\left(25+15\right)\right]\)
\(=9000-\left[169-4.40\right]\)
\(=9000-\left[169-160\right]\)
\(=9000-9=8991\)
a.\(25.8^3-23.8^3=8^3.\left(25-23\right)=512.2=1024\)
b. \(5^4-2.5^3=5^3.\left(5-2\right)=125.3=375\)
c. \(2.4^3-4^3.7-6.4^3=4^3.\left(2-7-6\right)\)\(=64.\left(-11\right)=-704\)
d. \(3^2.10^3-\left[13^2-\left(5^2.4+2^2.15\right)\right]=\)\(3^2.10^3-\left[13^2-\left(100+60\right)\right]\) \(=3^2.10^3-\left(13^2-160\right)=9000-9=8991\)
\(\dfrac{6^3.7-6^3.12}{6^3.\left(5^3-5^2\right)}\)
\(\dfrac{6^3.7-6^{13}.12}{6^3\left(5^3-5^2\right)}=\dfrac{6^3\left(7-12\right)}{5^3\left(125-25\right)}=\dfrac{-5}{100}=-\dfrac{1}{20}\)
\(=\dfrac{6^3\left(7-12\right)}{6^3\left(125-25\right)}=\dfrac{-5}{100}=-\dfrac{1}{20}\)
\(\dfrac{6^3.7-6^3.12}{6^3.\left(5^3-5^2\right)}=\dfrac{6^3.\left(-5\right)}{6^3.100}=\dfrac{1}{-20}\)
Tính hợp lí : \(4.24.5^2-\left(3^3.18+3^3.12\right)\)
4 x 24 x 52 - (33 x 18 + 33 x 12 )
= 4 x 24 x 25 - ( 27 x 18 + 27 x 12 )
= 100 x 24 - [ 27 x ( 28 + 12 )]
= 2400 - ( 27 x 30 )
= 2400 - 810
= 1590
4.24.52 - ( 33.18 + 33.12)
= 4.24.25 - 33( 18 + 12 )
= 100.24 - 33.30
=2400 - 27.30
= 2400 - 810 = 1590
4 . 24 . 52 - ( 33 . 18 + 33 . 12 )
=4 . 24 . 10 - ( 27 . 18 + 27 . 12 )
= 96 . 10 - [ 27. (12 + 18 )
= 960 - [27 . 30)
=960 - 810
= 150
Vậy giá trị của biểu thức đã cho là 150
Rút gọn:
\(\dfrac{\left(-2\right)^3.9^3.5^5.7.8}{3^6.4^4.25^3.14}\)
\(=\dfrac{\left(-2\right)^2.\left(-2\right).9.9.9.5^2.5^2.5.7.8}{3^2.3^2.3^2.4.4^2.25.25.25.14}=\dfrac{-2.5.7.8}{4^2.14}=\dfrac{-560}{224}=\dfrac{-5}{2}\)
\(\dfrac{\left(-2\right)^3.9^3.5^5.7.8}{3^6.4^4.25^3.14}=-\dfrac{2^3.\left(3^2\right)^3.5^5.7.2^3}{3^6.\left(2^2\right)^4.\left(5^2\right)^3.7.2}=-\dfrac{2^6.3^6.5^5.7}{2^9.3^6.5^6.7}=-\dfrac{1}{2^3.5}=-\dfrac{1}{40}\)
Tính nhanh các bài toán sau:
a) \(\left(12^3+1\right).\left(12^3-1\right)-3^6.4^6\)
b) \(\left(20^2+18^2+16^2+...+4^2+2^2\right)-\left(19^2-17^2\right)\)
mik ko chép lại đề bài nha
a) = (123)2- 12- (36. 46)
= (126-1)- (3.4)6
= 126-1-126
= -1
Chứng minh rằng :
\(1.4+2.4^2+3.4^3+4.4^4+5.4^5+6.4^6⋮3\)
\(\left(\frac{-10}{3}\right)^5.\left(\frac{-6}{5}\right)^4\)
\(\frac{7^5.5^7}{35^7}\)
\(\frac{12^3+3.12^2+3^{^3}}{162}\)
\(\left(-\frac{10}{3}\right)^5.\left(-\frac{6}{5}\right)^4\)
\(=\frac{-2^5.5^5}{3^5}.\frac{2^4.3^4}{5^4}\)
\(=\frac{-2^9.5}{3}=-\frac{2560}{3}\)