a, x/147 = 5/7 ; b, x -2/36 = 7/12
2 | + | 2 | + … + | 2 | = | |
5 x 7 | 7 x 9 | 145 x 147 |
|
\(=\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+...+\dfrac{1}{145}-\dfrac{1}{147}\)
\(=\dfrac{1}{5}-\dfrac{1}{147}=\dfrac{142}{735}\)
\(\dfrac{2}{5.7}+\dfrac{2}{7.9}+...+\dfrac{2}{145.147}\)
\(=\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+...+\dfrac{1}{145}-\dfrac{1}{147}\)
\(=\dfrac{1}{5}-\dfrac{1}{147}\)
\(=\dfrac{147}{735}-\dfrac{5}{735}\)
\(=\dfrac{142}{735}\)
A = 1 x 3 x 5 x 7 ... 13 + 20
B = 147 x 247 x 347 - 13
thêm dấu ngoặc đơn vào biểu thức
a, 7 x 13 x 2 - 5 = 147
b, 15 x 7 +2 x 4 = 428
a) 7*(13*2-5)
b)(15*7+2)*4
Dấu * là dấu nhân nha bn
Ủng hộ mk nhaaa
5/7 = X/147
5/7 = X/147
X = 5/7 x 147
X = 5 x 21
X = 105
Mk lm rùi đó ai thấy thì k cho mk nha
\(\frac{5}{7}=\frac{X}{147}\)
\(x=\frac{5}{7}\cdot147\)
\(x=105.\)
Suy ra : 5.147=7x
=> x = \(\frac{5.147}{7}\)
a,6/15=8/y
b,x/5=6/10
c,2/3=12/x
d,24/26=x/12
e,14/56=1/x
g,x/125=2/2
h,6+x/33=7/11
i,5/7=y/147
k,5/7=y/147
l,4/x=y/21=28/49
m,3*x-5/60=2/3
n,2/3*x=3*9
o,24/120=x/5
Tình nhanh
a) 18x 76 +24x -150
b) 147+230+53+70
c) 7x 85+27 x 7-7 x 12
D) 2va3/5 -2/5x( 5/8-7/12)
B= 1037 + { 743 - [ 1031 - (+57) ] }
C= ( 125x 73 - 125 x 75): ( -25 x 2)
D= - 25 x ( 35 + 147)+ 35 x ( 25 + 147)
E= 125 x 9x (-4)x (-8) x 25 x 7
G= ( -3)2 + ( - 5)3 : /-5/
Tính :
a/ 114 x 6 = ....
b. 147 - (7 x 8) = .......
a/ 114 x 6 = 684
b. 147 - (7 x 8) = 147 – 56
= 91.
Tính :
a/ 114 x 6 = ....
b. 147 - (7 x 8) = .......
a/ 114 x 6 = 684 (0,5đ)
b. 147 - (7 x 8) = 147 – 56 (0,5đ)
= 91