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Câu b:
\(\frac{21}{8}:\frac{5}{6}+\frac{1}{2}:\frac{5}{6}\)
= \(\frac{63}{20}+\frac{3}{5}\)
= \(\frac{15}{4}\)
\(\left(\frac{21}{8}+\frac{1}{2}\right):\frac{5}{6}\)
\(\frac{25}{8}:\frac{5}{6}\)
\(\frac{25}{8}.\frac{6}{5}\)
\(\frac{30}{8}\)
a) (x + 1/3) : 4/5 = 5/2
x+1/3=5/2*4/5
x+1/3=2
x=2-1/3
x=5/3
b) ( x - 1/3) * 1/2 = 1/3
x-1/3=1/3:1/2
x-1/3=2/3
x=2/3+1/3
x=1
c) 12*1/2 + 15*3/6 < x < 4*2/5 * 1/2
27/2<x<4/5
vì 27/2>4/5 nên đề sai
d) 575 - (6x * 70) = 445
6x*70=575-445
6x*70=130
6x=130:70
6x=13/7
x=13/7:6
x=13/42
e) 8,75 * x + 3,75 * x + 28,7(thiếu dữ kiện)
f) 3/4 * x = 1/4 + 0,75
3/4*x=1
x=1:3/4
x=4/3
**** nhé
a) (x + 1/3) : 4/5 = 5/2
x + 1/3 = 5/2 . 4/5
x + 1/3 = 2
x = 2 - 1/3
x = 5/3
2/3 . x + 3/4 = 3
2/3 . x = 3 - 3/4
2/3 . x = 1/4
x = 1/4 : 2/3
x = 3/8
720 : {41-[2x . (-5)]} =120
41-[2x . (-5)] = 720 : 120
41-[2x . (-5)] = 6
2x . (-5) = 41 - 6
2x . (-5) = 35
2x = 35 :(-5)
2.x=-7
x=-7:2
x=-7/2=-3,5
chúc bạn học tốt nha
ủng hộ mk với nha
720:[41-(2×x-5)]=120
[41-(2×x-5)]=720:120
[41-(2×x-5)]=6
(2×x-5)=41-6
(2×x-5)=35
2×x=35+5
2x=40
x=40:2
vậy x=20
a) \(720:\left[41-\left(2x-5\right)\right]=120\)
\(\Rightarrow\left[41-\left(2.x-5\right)\right]=6\)
\(\Rightarrow2x-5=35\Rightarrow2x=40\Rightarrow x=20\)
b) \(4,8.5-x+100=250\)
\(\Rightarrow4,8.5-x=150\Rightarrow24-x=150\Rightarrow x=-126\)
c)+) \(\frac{3}{5}+\frac{2}{5}:x=1\Rightarrow\frac{2}{5}:x=\frac{2}{5}\Rightarrow x=1\)
+) \(\frac{3}{5}+\frac{2}{5}:x=\frac{1}{4}\Rightarrow\frac{2}{5}:x=\frac{-7}{20}\Rightarrow x=\frac{-8}{7}\)
Cậu có thể tham khảo bài làm trên đây ạ, chúc cậu hok tốt ^^
a) 10*(x-1)=15-5
10*(x-1)=10
(x-1)=10:10
(x-1)=1
x=1+1
x=2
b) x+1+x+2+x+3=18
3x+6=18
3x=18-6
3x=12
x=12:3
x=4
c) 17+2*(x+2)=25
2*(x+2)=25-17
2*(x+2)=8
x+2=8:2
x+2=4
x=4-2
x=2
d) x:17=82-17+26
x:17=91
x=91*17
x=1547
e) 147*x=441
x=441:147
x=3
g)(x:81)=330:10:11
(x:81)=3
x=3*81
x=243
i)x+1+x+2+x+3+x+4+x+5=40
5x+15=40
5x=40-15
5x=25
x=5
Ủng hộ nha
bạn làm sao ấy đề mink viet khac ma ban vite mot neo
y x 5/6 = 7/4 - (1/2 + 1/3) = 7/4 - 5/6
Y X 5/6 = 11/12
Y = 11/12 X 6/5 = 33/30
a)13/17 < 15/19
a) 2/3 x X + 3/4 = 3
2/3 x X = 3 - 3/4
2/3 x X = 9/4
X = 9/4 : 2/3
X = 27/8
a. Ta có : \(\frac{13}{17}=\frac{247}{323};\frac{15}{19}=\frac{255}{323}\)
Vì 255 > 247 nên 247/323 < 255/323
Hay \(\frac{13}{17}< \frac{15}{19}\)
b. \(\frac{2}{3}\times x+\frac{3}{4}=3\)
\(\frac{2}{3}\times x=3-\frac{3}{4}\)
\(\frac{2}{3}\times x=\frac{9}{4}\)
\(x=\frac{9}{4}:\frac{2}{3}\)
\(x=\frac{27}{8}\)
c. \(720:\left[41-\left(2\times x-5\right)\right]=120\)
\(\left[41-\left(2\times x-5\right)\right]=720:120\)
\(41-\left(2\times x-5\right)=6\)
\(2\times x-5=35\)
\(2\times x=40\)
\(x=20\)
Chỉ làm bài khó thôi nhé:::::::::::::::
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x.\left(x+1\right)}=\frac{2016}{2018}\)
\(\Rightarrow\frac{2}{6}+\frac{2}{12}+\frac{2}{20}+....+\frac{2}{x.\left(x+1\right)}=\frac{2016}{2018}\)
\(\Rightarrow2.\left(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{x.\left(x+1\right)}\right)=\frac{2016}{2018}\)
\(\Rightarrow\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{x.\left(x+1\right)}=\frac{1013}{2018}\)
\(\Rightarrow\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{x}-\frac{1}{x+1}=\frac{1013}{2018}\)
\(\Rightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{1013}{2018}\)
\(\Rightarrow\frac{1}{x+1}=\frac{1}{2018}\Rightarrow x+1=2018\Rightarrow x=2017\)