(4 -12/10 ) ː 2 + 30%
Bài1 tính:
a)\(\dfrac{2}{5}\)+\(\dfrac{5}{12}\); b)\(\dfrac{2}{3}\) - \(\dfrac{3}{8}\); c)\(\dfrac{3}{7}\) ✖ \(\dfrac{4}{9}\); d) \(\dfrac{11}{10}\) - \(\dfrac{2}{5}\) ː \(\dfrac{2}{3}\)
2/5+5/12
=49/60
2/3-3/8
=7/24
3/7.4/9
=4/21
11/10-2/5:2/3
=11/10-3/5
=1/2
a, 9/25 ː 1 =
b1,12 . -9/8 = b2, 12 ː -9/8 =
c1, 3 . -5/6 = c2, 3 ː -5/6 =
1.Tìm x
a, x ː 2,2 = (28,7 - 13,5 ). 2
b, (3 3/4 . x +75%) ː 2/3 = -1
c, 4x - ( 3 + 5x ) = 14
a: =>x:2,2=15,2x2=30,4
=>x=66,88
b: =>(15/4x+3/4)=-2/3
=>15/4x=-17/12
hay x=-17/45
a \(\dfrac{x}{y}\) - \(\dfrac{3}{8}\) = \(1\dfrac{1}{2}\) b \(\dfrac{4}{9}\) ː \(\dfrac{x}{y}\) = \(1\dfrac{1}{2}\)
giup mik với mik cần gấp
450 ː [41 - (2x -5)] = 3 mũ 2 x 5
450 : [ 41 - ( 2x - 5 )] = 32 . 5
450 : [ 41 - ( 2x - 5 )] = 9 . 5
450 : [ 41 - ( 2x - 5 )] = 45
41 - ( 2x - 5) = 450 : 45
41 - ( 2x - 5 ) = 10
2x - 5 = 41 - 10
2x - 5 = 31
2x = 31 + 5
2x = 36
x = 36 : 2
x = 18
Vậy x = 18
Học tốt!!!
\(450:\left[41-\left(2x-5\right)\right]3^{2.5}\)
450 : [41 - 2x + 5] = 9 . 5
450 : [46 - 2x] = 45
46 - 2x = 10
2x = 36
x = 18
Tập hợp ước số của số 60 là:
A. Ư(60) = {1; 2; 3; 5; 12; 20; 30; 60}
B. Ư(60) = {1; 2; 3; 4; 15; 20; 30; 60}
C. Ư(60) = {1; 2; 3; 4; 5; 12; 15; 20; 30; 60}
D. Ư(60) = {1; 2; 3; 4; 5; 6; 10; 12 15; 20; 30; 60}
a) 20\16 - 3\4 b) 30\45 - 2\5
c) 10\12 -3\4 d)12\9 -1\4
a: =5/4-3/4=2/4=1/2
b: =30/45-18/45=12/45=4/15
c: =10/12-9/12=1/12
d: =4/3-1/4=16/12-3/12=13/12
\(M=\frac{\text{2 . 6 . 10 + 4 . 12 . 20 + 6 . 18 . 30 + ..... + 20 . 60 . 100}}{\text{1 . 2 . 3 + 2 . 4 . 6 + 3 . 6 . 9 + ..... + 10 . 20 . 30}}\)
Rút gọn biểu thức trên nha.
\(M=\frac{2.6.10+4.12.20+...+20.60.100}{1.2.3+2.4.6+...+10.20.30}=\frac{2.6.10.1^3+2.6.10.2^3+...+2.6.10.10^3}{1.2.3.1^3+1.2.3.2^3+...+1.2.3.10^3}\)
\(=\frac{2.6.10.\left(1^3+2^3+...+10^3\right)}{1.2.3.\left(1^3+2^3+...+10^3\right)}=\frac{2.6.10}{1.2.3}=20\)
vậy M=20
Bài 2: Tính
a. 20/16 - 3/4
b. 30/45 - 2/5
c. 10/12 - 3/4
d. 12/9 - 1/4
a:=5/4-3/4=2/4=1/2
b: =2/3-2/5=10/15-6/15=4/15
c: =10/12-9/12=1/12
d: =4/3-1/4=16/12-3/12=13/12
\(a,=\dfrac{5}{4}-\dfrac{3}{4}=\dfrac{2}{4}\\ b,=\dfrac{30}{45}-\dfrac{18}{45}=\dfrac{12}{45}\\ c,=\dfrac{10}{12}-\dfrac{9}{12}=\dfrac{1}{12}\\ d,=1\dfrac{1}{12}\)
\(a,\dfrac{20}{16}-\dfrac{3}{4}=\dfrac{5}{4}-\dfrac{3}{4}=\dfrac{2}{4}=\dfrac{1}{2}\\ b,\dfrac{30}{45}-\dfrac{2}{5}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10}{15}-\dfrac{6}{15}=\dfrac{4}{15}\\ c,\dfrac{10}{12}-\dfrac{3}{4}=\dfrac{5}{6}-\dfrac{3}{4}=\dfrac{10}{12}-\dfrac{9}{12}=\dfrac{1}{12}\\ d,\dfrac{12}{9}-\dfrac{1}{4}=\dfrac{4}{3}-\dfrac{1}{4}=\dfrac{16}{12}-\dfrac{3}{12}=\dfrac{13}{12}\)