![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a,
\(B=\left(\dfrac{5}{7}\cdot0,6-5:\dfrac{7}{2}\right)\cdot\left(40\%-1,4\right)\cdot\left(-2\right)^3\\ =\left(\dfrac{5}{7}\cdot\dfrac{3}{5}-5\cdot\dfrac{2}{7}\right)\cdot\left(\dfrac{2}{5}-\dfrac{7}{5}\right)\cdot\left(-8\right)\\ =\left(\dfrac{3}{7}-\dfrac{10}{7}\right)\cdot\left(-1\right)\cdot\left(-8\right)\\ =\left(-1\right)\cdot\left(-1\right)\cdot\left(-8\right)\\ =\left(-8\right)\)
b,
\(\dfrac{1}{2}\cdot x+\dfrac{3}{5}\cdot\left(x-2\right)=3\\ \dfrac{1}{2}x+\dfrac{3}{5}x-\dfrac{6}{5}=3\\ x\left(\dfrac{1}{2}+\dfrac{3}{5}\right)=3+\dfrac{6}{5}\\ x\cdot\dfrac{11}{10}=\dfrac{21}{5}\\ x=\dfrac{21}{5}:\dfrac{11}{10}\\ x=\dfrac{42}{11}\\ Vậy......\)
![](https://rs.olm.vn/images/avt/0.png?1311)
B)
( x + 4/3 ) * 7/4 = 5 - 7/6
( x + 4/3) * 7/4 = 5/1 - 7/6
( x + 4/3) * 7/4 = 30/6 - 7/6
( x + 4/3) * 7/4 = 23/6
( x + 4/3) = 23/6 : 7/4
( x+ 4/3) = 23/6 . 4/7
( x+ 4/3) = 46/21
x = 46/21 - 4/3
x = 46/21 - 28/21
x = 18/21 = 6/7
Tk vs kb hộ mk nha! thank u
may cau khac ko kho lam dau chi co cau d thoi.
(100%-50%+40%):x=18%+30%:x
90%:x=18%+30%:x
18%=90%:x-30%:x
18%=60%:x
X=60%:18%
x=..................................................................................................
xong roi do a cho minh nhe
![](https://rs.olm.vn/images/avt/0.png?1311)
a, 5(x – 7) = 0
x – 7 = 0
x = 7
b, 95 – 5(x+2) = 45
5(x+2) = 40
x+2 = 8
x = 6
c, 6 2 x + 2 3 + 40 = 100
6(2x+8) = 60
2x+8 = 10
x = 1
d, 3(3x+9)+6 = 96
3(3x+9) = 90
3x+9 = 30
3x = 27
x = 9
e, 2 6 + 5 + x = 3 4
5+x = 81–64
5+x = 17
x = 12
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 22 ( x + 32 ) - 5 = 55
=>4(x+9)-5=55
=>4(x+9)=60
=>x+9=15
=>x=6
b)7 ( x + 52 ) - 20 = 190
=>7(x+25)=210
=>x+25=30
=>x=5
c)6 ( x + 23 ) + 40 = 100
=>6(x+8)+40=100
=>6(x+8)=60
=>x+8=10
=>x=2
![](https://rs.olm.vn/images/avt/0.png?1311)
2:
a: =>2/3:x=1,4-2,4=-1
=>x=-2/3
b: =>x/5=25/30-19/30=6/30=1/5
=>x=1
3:
Số học sinh giỏi là 40*1/4=10 bạn
Số học sinh khá là 30*3/5=18 bạn
Số học sinh TB là 30-18=12 bạn
![](https://rs.olm.vn/images/avt/0.png?1311)
a)(3/4-5/6+7/12).(-12/7)=1/2.(-12/7)
=6/7
b)1,4.15/49-(4/5+2/3):11/5=1,4.15/49-22/15:11/5
=3/7-2/3=-5/21
(3/4-5/6+7/12)×(-12/7)
=(9/12-10/12+7/12)×(-12/7)
=(-1/12+7/12)×(-12/7)
=6/12×(-12/7)
=1/2×(-12/7)
=-12/14
=-6/7