chỉ mình mấy câu này nha
câu 1 : 1/3:x-2/3=5/6+7/8
câu 2 :2/5 -x :3/5=6/7
câu 3: 4/5-26/m=-8/15
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
18 tháng 9 2023
1. a
\(\dfrac{8}{5}-\dfrac{5}{6}\cdot\dfrac{3}{4}\)
\(=\dfrac{8}{5}-\dfrac{5\cdot3}{3\cdot2\cdot4}\)
\(=\dfrac{8}{5}-\dfrac{5}{8}=\dfrac{39}{40}\)
1.b
\(=\dfrac{7}{8}+\dfrac{5}{6}\cdot\dfrac{3}{2}\)
\(=\dfrac{7}{8}+\dfrac{5\cdot3}{3\cdot2\cdot2}\)
\(=\dfrac{7}{8}+\dfrac{5}{4}=\dfrac{17}{8}\)
2.a
\(\dfrac{4}{5}+x=\dfrac{11}{10}\)
\(x=\dfrac{11}{10}-\dfrac{4}{5}=\dfrac{3}{10}\)
2.b
\(x-\dfrac{3}{4}=\dfrac{5}{7}\)
\(x=\dfrac{5}{7}+\dfrac{3}{4}=\dfrac{41}{28}\)
6 tháng 2 2016
1.4x - 5(-3+x)=7
4x - 5(x-3) =7
4x - 5x + 15=7
-1x + 15=7
-1x =-8
=> x =8
2.5(x-3) - 2(x+6)=9
5x - 15 -2x -12=9
5x - 2x -15 - 12=9
5x - 2x=9 + 12 + 15
5x - 2x= 36
3x = 36
=> x = 12
3.4(x-1) - 3(x-2)=15
4x - 4 - 3x + 6=15
4x - 3x =15 - 6 + 4
4x - 3x = 13
=> x = 13
Nhớ mink nhoa pn
28 tháng 2 2017
ban a toán lớp mấy thì toán vậy bạn có trả lời được ko mà còn ra vẻ hả bạn 'doraemi'
BD
4
17 tháng 3 2018
7/8 + 3/4=13/8
3/2 + 4/5=23/10
6/7 * 5/6=5/7
5/6 : 8/9=15/16
17 tháng 3 2018
\(\frac{7}{8}+\frac{3}{4}=\frac{28}{32}+\frac{24}{32}=\frac{52}{32}\)
\(\frac{3}{2}+\frac{4}{5}=\frac{15}{10}+\frac{8}{10}=\frac{23}{10}\)
\(\frac{6}{7}x\frac{5}{6}=\frac{30}{42}\)
\(\frac{5}{6}:\frac{8}{9}=\frac{5}{6}x\frac{9}{8}=\frac{45}{48}\)
14 tháng 6 2023
a: =7/8:(2/9-18+1/36)-5/12
=-7/142-5/12=-397/852
b: =3/7(4/9+5/9:6/12)=2/3
c: =5^8(16/31-47/31)+1/3=-5^8+1/3
d: =7/2(3/8+5/8:4/15)=609/64
5 tháng 8 2017
khỏi chép đề nha
a\Câu 1:
200 : ( 15 - x ) = 15 + 5
200 : ( 15 - x ) = 20
15 - x = 200 : 20
15 - x = 10
x = 15 - 10
x = 5
Câu 2:
63 : ( x - 5 ) = 22 -1
63 : ( x - 5 ) = 21
x - 5 = 63 : 21
x - 5 = 3
x = 3 + 5
x = 8
19 tháng 1 2022
Câu 1:
\(\left(x-2\right)\left(x^2+2x+4\right)+25x=x\left(x+5\right)\left(x-5\right)+8\)
\(\Leftrightarrow x^3-8+25x=x\left(x^2-25\right)+8\)
\(\Leftrightarrow x^3-8+25x=x^3-25x+8\)
\(\Leftrightarrow x^3-8+25x-x^3+25x-8=0\)
\(\Leftrightarrow50x-16=0\)
\(\Leftrightarrow50x=16\)
\(\Leftrightarrow x=\dfrac{8}{25}\)
B
19 tháng 1 2022
Câu 2 :
\(\dfrac{x+5}{4}+\dfrac{3+2x}{3}=\dfrac{6x-1}{3}-\dfrac{1-2x}{12}\)
<=> \(\dfrac{3\left(x+5\right)}{12}+\dfrac{4\left(3+2x\right)}{12}=\dfrac{4\left(6x-1\right)}{12}-\dfrac{1-2x}{12}\)
<=>\(\dfrac{3x+15+12+8x}{12}=\dfrac{24x-4-1+2x}{12}\)
<=> 3x + 15 + 12 + 8x = 24x - 4 - 1 +2x
<=> 11x+27 = 26x -5
<=> ( 26x - 5 ) - ( 11x + 27 ) = 0
<=> 15x - 32 = 0
<=> 15x = 32
<=> x = \(\dfrac{32}{15}\)
\(\frac{1}{3}:x-\frac{2}{3}=\frac{5}{6}+\frac{7}{8}\)
\(\frac{1}{3}:x-\frac{2}{3}=\frac{41}{24}\)
\(\frac{1}{3}:x=\frac{19}{8}\)
\(x=\frac{8}{57}\)
\(\frac{2}{5}-x:\frac{3}{5}=\frac{6}{7}\)
\(x:\frac{3}{5}=\frac{-16}{35}\)
\(x=\frac{-48}{175}\)
\(\frac{4}{5}-\frac{26}{m}=\frac{-8}{15}\)
\(\frac{26}{m}=\frac{4}{3}\)
=> 26 x 3 = m x 4
78 = m x 4
m = 19,5
Câu 1 :\(\frac{1}{3}\div x-\frac{2}{3}=\frac{5}{6}+\frac{7}{8}\)
\(\Leftrightarrow\frac{1}{3x}=\frac{5}{6}+\frac{7}{8}+\frac{2}{3}\)
\(\Leftrightarrow\frac{1}{3x}=\frac{4\cdot5}{24}+\frac{7\cdot3}{24}+\frac{2\cdot8}{24}\)
\(\Leftrightarrow\frac{1}{3x}=\frac{20}{24}+\frac{21}{24}+\frac{16}{24}\)
\(\Leftrightarrow\frac{1}{3x}=\frac{57}{24}\)
\(\Leftrightarrow24=57\cdot3x\)
\(\Leftrightarrow24=171x\)
\(\Leftrightarrow x=\frac{24}{171}=\frac{8}{57}\)
Câu 2: \(\frac{2}{5}-x\div\frac{3}{5}=\frac{6}{7}\)
\(\Leftrightarrow\frac{-5x}{3}=\frac{6}{7}-\frac{2}{5}\)
\(\Leftrightarrow\frac{-5x}{3}=\frac{5\cdot6}{35}-\frac{2\cdot7}{35}\)
\(\Leftrightarrow\frac{-5x}{3}=\frac{30}{35}-\frac{14}{35}\)
\(\Leftrightarrow-\frac{5x}{3}=\frac{16}{35}\)
\(\Leftrightarrow-175x=48\)
\(\Leftrightarrow x=-\frac{48}{175}\)
Câu 3: \(\frac{4}{5}-\frac{26}{m}=-\frac{8}{15}\)
\(\Leftrightarrow\frac{26}{m}=\frac{4}{5}-\left(-\frac{8}{15}\right)\)
\(\Leftrightarrow\frac{26}{m}=\frac{4}{5}+\frac{8}{15}\)
\(\Leftrightarrow\frac{26}{m}=\frac{12}{15}+\frac{8}{15}\)
\(\Leftrightarrow\frac{26}{m}=\frac{20}{15}\)
\(\Leftrightarrow20m=26\cdot15=390\)
\(\Leftrightarrow m=\frac{390}{20}=\frac{39}{2}\)