![](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)
\(x+2\dfrac{1}{4}=4\dfrac{5}{6}\)
\(x=4\dfrac{5}{6}-2\dfrac{1}{4}\)
\(x=4+\dfrac{5}{6}-2-\dfrac{1}{4}\)
\(x=2+\dfrac{7}{12}\)
\(x=\dfrac{31}{12}\)
_____________
\(9\dfrac{3}{5}-x=3\dfrac{3}{8}\)
\(x=9\dfrac{3}{5}-3\dfrac{3}{8}\)
\(x=9+\dfrac{3}{5}-3-\dfrac{3}{8}\)
\(x=6+\dfrac{9}{40}\)
\(x=\dfrac{249}{40}\)
\(x+2\dfrac{1}{4}=4\dfrac{5}{6}\)
\(=>x+\dfrac{9}{4}=\dfrac{29}{6}\)
\(=>x=\dfrac{29}{6}-\dfrac{9}{4}=\dfrac{58}{12}-\dfrac{27}{12}\)
\(=>x=\dfrac{31}{12}\)
_______
\(9\dfrac{3}{5}-x=3\dfrac{3}{8}\)
\(=>\dfrac{48}{5}-x=\dfrac{27}{8}\)
\(=>x=\dfrac{48}{5}-\dfrac{27}{8}=\dfrac{384}{40}-\dfrac{135}{40}\)
\(=>x=\dfrac{249}{40}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) x × 7/9 = 2/3 + 2 1/2
x × 7/9 = 2/3 + 5/2
x × 7/9 = 19/6
x = 19/6 : 7/9
x = 57/14
b) 5/7 + x : 9/4 = 4/3
x : 9/4 = 4/3 - 5/7
x : 9/4 = 13/21
x = 13/21 × 9/4
x = 39/28
Một tốp thợ có 120 người dự địnhnlamf trong 50 ngày . Khi bắt đầu làm có một số người đến làm thêm nên làm xong công việc đó trong 30 ngày . Hỏi có bao nhiêu người đến thêm?
![](https://rs.olm.vn/images/avt/0.png?1311)
c] 7 * x + 8 * x + 9 * x + .... + 100 * x = 1025
(7+8+9+...+100)*x=1025
Coi A= 7+8+...+100
Số các số hạng của A là:
(100-7):1+1=94 (số)
=>A=(100+7)*94:2=5029
Ta lại có:
5029*x=1025
=>x=1025:5019=1025/5019
a, \(x.\left(\frac{3}{2}+\frac{1}{4}-\frac{1}{2}\right)=x.\left(\frac{6}{4}+\frac{1}{4}-\frac{2}{4}\right)=\frac{10}{9}\)
\(x.\frac{5}{4}=\frac{10}{9}\)
\(x=\frac{10}{9}:\frac{5}{4}=\frac{10}{9}.\frac{4}{5}=\frac{8}{9}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
A) x/y-3/8=1 x/y-3/8=1/2 B)4/9:x/y=1 4/9:x/y=2/3
x/y=1+3/8 x/y=1/2+3/8 x/y=4/9:1 x/y=4/9:2/3
x/y=8/8+3/8 x/y=4/8+3/8 x/y=4/9 x/y=2/3
x/y=11/8 x/y=7/8
![](https://rs.olm.vn/images/avt/0.png?1311)
1) 2,75 - 5/6 × 2/5 = 2,75 - (5/6) × (2/5) = 2,75 - 1/3 = 2,75 - 0,33 = 2,42
2) 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 3/4) - 3/5 = 1,25 - (5/6 - 9/12) - 3/5 = 1,25 - (10/12 - 9/12) - 3/5 = 1,25 - 1/12 - 3/5 = 1,25 - 0,08 - 0,6 = 1,25 - 0,68 = 0,57
3) 4/9 × 0,75 + 8/5 + 3,125 = (4/9) × 0,75 + 8/5 + 3,125 = 0,44 + 8/5 + 3,125 = 0,44 + 1,6 + 3,125 = 0,44 + 4,725 = 5,165
4) 1,125 - 4/7 - 0,12 = 1,125 - (4/7) - 0,12 = 1,125 - 0,57 - 0,12 = 0,435 - 0,12 = 0,315
5) (1/3 + 0,4) × 3,5 + (1/6 + 0,75) × 6/5
![](https://rs.olm.vn/images/avt/0.png?1311)
c] 7 * x + 8 * x + 9 * x + .....+ 100 * x = 1025
=> x (7 + 8 + 9 +...+ 100) = 1025
=> x * 5029 = 1025
=> x = 1025/5029
![](https://rs.olm.vn/images/avt/0.png?1311)
ừ thì giải theo cách lớp 5
\(\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{10}\right)\times x=\frac{1}{9}+\frac{2}{8}+...+\frac{9}{1}\)
Gọi vế phải là A
\(A=\frac{10}{9}+\frac{10}{8}+...+\frac{10}{1}-9\)
\(A=10\times\left(\frac{1}{9}+\frac{1}{8}+\frac{1}{7}+...+\frac{1}{2}\right)+1\)
\(A=10\times\left(\frac{1}{10}+\frac{1}{9}+\frac{1}{8}+...+\frac{1}{2}-\frac{1}{10}\right)+1\)
\(A=10\times\left(\frac{1}{10}+\frac{1}{9}+...+\frac{1}{2}\right)-1+1\)
\(\Rightarrow VP=10\times A\)
\(\Rightarrow x=10\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(x+9\right)+\left(x-2\right)+\left(x+7\right)+\left(x-4\right)+\left(x+5\right)+\left(x-6\right)+\left(x+3\right)+\left(x-8\right)+\left(x+1\right)=95\)
\(x+9+x-2+x+7+x-4+x+5+x-6+x+3+x-8+x+1=95\)
\(\left(x\times9\right)+\left(9-2+7-4+5-6+3-8+1\right)=95\)
\(x\times9+5=95\)
\(x\times9=95-5\)
\(x\times9=90\)
\(x=90:9\)
\(x=10\)
(x + 9) + (x - 2) + (x + 7) + (x - 4) + (x + 5) + (x - 6) + (x + 3) + (x - 8) + (x + 1) = 95
x + 9 + x - 2 + x + 7 + x - 4 + x + 5 + x - 6 + x + 3 + x - 8 + x + 1
(x + x + x + x + x + x + x + x + x) + (9 - 8 + 7 - 6 + 5 - 4 + 3 - 2 + 1) = 95
9 × x + 5 = 95
9 × x = 95 - 5
9 × x = 90
x = 90 : 9
x = 10
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 4/7 x X = 1/5 + 2/3
=> 4/7 x X = 3/15 + 10/15
=> 4/7 x X = 13/15
=> X = 13/15 : 4/7
=> X = 13/15 x 4/7 = 52/105
a ) 4 / 7 x X = 1 / 5 + 2 / 3
= > 4 / 7 x X = 3 / 1 5 + 1 0 / 1 5
= > 4 / 7 x X = 1 3 / 1 5
= > X = 1 3 / 1 5 : 4 / 7
= > X = 1 3 / 1 5 x 4 / 7
= 5 2 / 1 0 5
\(\dfrac{8}{9}\div x+\dfrac{4}{9}\times\dfrac{1}{3}=3\dfrac{1}{3}\)
\(\dfrac{8}{9}\div x+\dfrac{4}{27}=\dfrac{10}{3}\)
\(\dfrac{8}{9}\div x=\dfrac{10}{3}-\dfrac{4}{27}\)
\(\dfrac{8}{9}\div x=\dfrac{86}{27}\)
\(x=\dfrac{8}{9}\div\dfrac{86}{27}\)
\(x=\dfrac{8}{9}\times\dfrac{27}{86}\)
\(x=\dfrac{12}{43}\)
Vậy \(x=\dfrac{12}{43}\)
\(\dfrac{8}{9}:x+\dfrac{4}{9}\times\dfrac{1}{3}=3\dfrac{1}{3}\)
=>\(\dfrac{8}{9}:x=\dfrac{10}{3}-\dfrac{4}{27}=\dfrac{90}{27}-\dfrac{4}{27}=\dfrac{86}{27}\)
=>\(x=\dfrac{8}{9}:\dfrac{86}{27}=\dfrac{8}{9}\times\dfrac{27}{86}=\dfrac{4}{43}\times3=\dfrac{12}{43}\)