Tính: 25/27 – 5/6 x 2/3 = ………..
Tính: 25/27 – 5/6 x 2/3 = ………..
\(\frac{25}{27}-\frac{5}{6}\times\frac{2}{3}\)
\(=\frac{25}{27}-\frac{5}{9}\)
\(=\frac{25}{27}-\frac{15}{27}\)
\(=\frac{25-15}{27}\)
\(=\frac{10}{27}\)
\(\frac{25}{27}-\frac{5}{6}\)x\(\frac{2}{3}=\frac{25}{27}-\frac{5}{9}=\frac{25}{27}-\frac{15}{27}=\frac{10}{27}\)
tính bằng cách thuận tiện nhất:
( 2/3 x 4/5) x 5/6 (4/5 + 5/4) x 3/4 27/12 + 17/6 - 25/36 - 15/6
`(2/3xx4/5)xx5/6`
`=2/3xx4/5xx5/6`
`=2/3xx4/6`
`=2/3xx2/3`
`=1`
__
`(4/5+5/4)xx3/4`
`=(16/20+25/20)xx3/4`
`=41/20xx3/4`
`=123/80`
__
`27/12+17/6-25/36-15/6`
`=(27/12-25/36)+(17/6-15/6)`
`=(81/36-25/36)+2/6`
`=56/36+2/6`
`=56/36+12/36`
`=68/36`
`=17/9`
B1 / Tính nhanh :
a/ 37.(27+25)-27(37+25)
b/ 3. (-5+3)+7(2-5)
c/ -3.(2-7)-6.(8-5)
Bài 2. Tính bằng cách thuận tiện nhất.
( 2/3 x 4/5 ) x 5/6
(4/5 + 5/4 ) x 3/4
11/23 + 2/23 + 9/23 + 18/23
27/12 + 17/6 - 25/36 - 15/6
TL:
8/15 x 5/6 = 40/90 = 4/9
41/20 x 3/4 = 123/80
(11/23 + 9/23) + (18/23 + 2/23) = 20/23 + 20/23 = 40/43
HT
\(\left(\frac{2}{3}\times\frac{4}{5}\right)\times\frac{5}{6}\) = \(\frac{2}{3}\times\frac{4}{5}\times\frac{5}{6}\)=\(\frac{2\times4\times5}{3\times5\times6}\)=\(\frac{2\times4\times5}{3\times5\times2\times3}\)=\(\frac{4}{9}\)
\(\frac{11}{23}+\frac{2}{23}+\frac{9}{23}+\frac{18}{23}\)=\(\frac{\left(11+9\right)+\left(18+2\right)}{23}\)=\(\frac{20+20}{23}\)=\(\frac{40}{23}\)
\(\frac{27}{12}+\frac{17}{6}-\frac{25}{36}-\frac{15}{6}\)=\(\left(\frac{27}{12}-\frac{25}{36}\right)+\left(\frac{17}{6}-\frac{15}{6}\right)\)=\(\frac{14}{9}+\frac{2}{6}\)=\(\frac{17}{9}\)
/HT\
Nhập các bạn toàn bắt tớ làm à ngu gò mà làm
1, 7x+6(3-x)=27-20+73
2,6x-5(x-7)=(27-514)-486-73)
3,2x-6=3(x-5)+25+27-15-17
4, 4(x-5)-3(x+5)=2579-2578
5,/x-5/-7(x+4)=5-7x
6,3/x+4/-2(x-1)=7-2x
7, 2/x-6/+7x-2=/x-6/+7x
8,/x+8/+5(x-2)=5x-10:2
9, /x+2/-6(x-4)=20-6x
1: Ta có: 7x+6(3-x)=27-20+73
\(\Leftrightarrow7x+18-6x=80\)
\(\Leftrightarrow x=80-18=62\)
Vậy: x=62
2: Ta có: \(6x-5\left(x-7\right)=\left(27-514\right)-486-73\)
\(\Leftrightarrow6x-5x+35=27-514-486-73\)
\(\Leftrightarrow x+35=-1046\)
\(\Leftrightarrow x=-1081\)
Vậy: x=-1081
Thực hiện phép tính
a)\(\dfrac{5^{16}.27^{7}}{125^{5}.9^{11}}\)
b)\((-0,2)^{2}.5-\dfrac{2^{13}.27^{3}}{4^{6}.9^{5}}\)
c)\(\dfrac{5^{6}+2^{2}.25^{3}+2^{3}.125^{2}}{26.5^{6}}\)
\(a,\dfrac{5^{16}\cdot27^7}{125^5\cdot9^{11}}=\dfrac{5^{16}\cdot\left(3^3\right)^7}{\left(5^3\right)^5\cdot\left(3^2\right)^{11}}\)
\(=\dfrac{5^{16}\cdot3^{21}}{5^{15}\cdot3^{22}}=\dfrac{5}{3}\)
\(b,\left(-0,2\right)^2\cdot5-\dfrac{2^{13}\cdot27^3}{4^6\cdot9^5}\)
\(=0,04\cdot5-\dfrac{2^{13}\cdot\left(3^3\right)^3}{\left(2^2\right)^6\cdot\left(3^2\right)^5}\)
\(=0,2-\dfrac{2^{13}\cdot3^9}{2^{12}\cdot3^{10}}\)
\(=0,2-\dfrac{2}{3}\)
\(=-\dfrac{7}{15}\)
\(c,\dfrac{5^6+2^2\cdot25^3+2^3\cdot125^2}{26\cdot5^6}\)
\(=\dfrac{5^6+2^2\cdot\left(5^2\right)^3+2^3\cdot\left(5^3\right)^2}{5^6\cdot26}\)
\(=\dfrac{5^6+4\cdot5^6+8\cdot5^6}{5^6\cdot26}\)
\(=\dfrac{5^6\left(1+4+8\right)}{5^6\cdot26}\)
\(=\dfrac{13}{26}\)
\(=\dfrac{1}{2}\)
#\(Toru\)
\(a,\dfrac{5^{16}.27^7}{125^5.9^{11}}=\dfrac{\left(5^2\right)^8.9^7.3^7}{25^5.5^5.9^{11}}\\ =\dfrac{25^8.9^7.\left(3^2\right)^3.3}{25^5.\left(5^2\right)^2.5.9^{11}}=\dfrac{25^8.9^7.9^3.3}{25^5.25^2.5.9^{11}}\\ =\dfrac{25^8.9^{10}.3}{25^7.5.9^{11}}=\dfrac{25^7.9^{10}.25.3}{25^7.9^{10}.5.9}\\ =\dfrac{25.3}{5.9}=\dfrac{5.5.3}{5.3.3}=\dfrac{5}{3}\)
Tính
a, 27^3:3^2
b, (3/5)^15 x (9/25)^5
c, 45^10 x 5^10/75^10
d, 4^6 x 9^5+6^9 x 120/8^4 x 3^12-6^11
a, 3^9:3^2=3^7
b, (3/5)^15:(3/5)^10=(3/5)^5
c, (5.3.3)^10.5^10 / (5.5.3)^10=5^10.3^10.3^10.5^10 / 5^10.5^10.3^10=5^20.3^20 / 5^20.3^10=3^10
bài 1: Tính
a} 5/12 + 1/3 x 3/5 =
B 7/5 - 4/9 : 2/5 =
C 2/5 x 1/4 : 2/5 =
bài 2: Tìm y
a 42/25 : y/5 = 5/6
b 27/y : 9/4 = 3/7
bài 2
a)42/25:y/5=5/6
y=10,08
b)27/y:9/4=3/7
y=28
Bài 10: Tính giá trị của biểu thức
1/ (-25). ( -3). x với x = 4
2/ (-1). (-4) . 5 . 8 . y với y = 25
3/ (2ab 2 ) : c với a = 4; b = -6; c = 12
4/ [(-25).(-27).(-x)] : y với x = 4; y = -9
5/ (a 2 - b 2 ) : (a + b) (a – b) với a = 5 ; b = -3