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a) 3 3/4 . x = 1 1/2
<=> 15/4 . x = 3/2
<=> x = 3/4 . 4/15
<=> x = 1/5
Vậy x = 1/5
b) 1 1/4 x + 1 1/2 = 1 1/4
<=> 5/4 . x + 3/2 = 5/4
<=> 5/4 . x = 5/4 - 3/2
<=> 5/4 . x = -1/4
<=> x = -1/4 . 4/5
<=> x = -1/5
Vậy x = -1/5
c) ( 3 1/3 - 1 1/2 x ) : 5/6 = 1 1/2
<=> ( 10/3 - 3/2 x ) : 5/6 = 3/2
<=> 10/3 - 3/2 x = 3/2 . 5/6
<=> 10/3 - 3/2 x = 5/4
<=> 3/2 . x = 10/3 - 5/4
<=> 3/2 . x = 25/12
<=> x = 25/12 . 2/3
<=> x = 25/18
Vậy x = 25/18
d) ( 3/7 x - 1 ) : 4 = -1/28
<=> 3/7 . x - 1 = -1/28 . 1/4
<=> 3/7 . x - 1 = -1/112
<=> 3/7 . x = -1/112 + 1
<=> 3/7 . x = 111/112
<=> x = 111/112 . 7/3
<=> x = 37/16
Vậy x = 37/16
e) | x - 3/4 | = 1
<=> x - 3/4 = 1
hoặc x - 3/4 = -1
<=> x = 1 + 3/4
hoặc x = -1 + 3/4
<=> x = 7/4
hoặc x = -1/4
Vậy x = 7/4 ; x = -1/4
f) | 2/3 . x + 1/3 | = 5/6
<=> 2/3 . x + 1/3 = 5/6
hoặc 2/3 . x + 1/3 = -5/6
<=> 2/3 . x = 5/6 - 1/3
hoặc 2/3 . x = -5/6 - 1/3
<=> 2/3 . x = 1/2
hoặc 2/3 . x = -7/6
<=> x = 1/2 . 3/2
hoặc x = -7/6 . 3/2
<=> x = 3/4
hoặc x = -7/4
Vậy x = 3/4 ; x = -7/4
1) 1/3 . x + (2/3 - 4/9) = -3/4
1/3 . x + 2/9 = -3/4
1/3 . x = -3/4 - 2/9
1/3 . x = -35/36
x = -35/36 : 1/3
x = -35/12
\(\left(\frac{1}{4}.x-\frac{1}{8}\right).\frac{3}{4}=\frac{1}{4}\)
<=> \(\frac{1}{4}x-\frac{1}{8}=\frac{1}{3}\)
<=> \(\frac{1}{4}x=\frac{11}{24}\)
<=> \(x=\frac{11}{6}\)
\(\frac{1}{2}:x+\frac{3}{4}=1\frac{2}{3}\)
<=> \(\frac{1}{2}:x+\frac{3}{4}=\frac{5}{3}\)
<=> \(\frac{x}{2}=\frac{11}{12}\)
=> \(12x=22\)
<=> \(x=\frac{11}{6}\)
\(2x-\frac{3}{7}=\frac{2}{7}+\frac{3}{4}\)
<=> \(2x-\frac{3}{7}=\frac{29}{28}\)
<=> \(2x=\frac{41}{28}\)
<=> \(x=\frac{41}{56}\)
\(25\%.x=42,6-3,28\)
<=> \(0,25x=39,32\)
<=> \(x=157,28\)
\(\frac{15}{12}.x+\frac{3}{7}.x=\frac{6}{5}-\frac{1}{2}\)
<=> \(\left(\frac{15}{12}+\frac{3}{7}\right).x=\frac{7}{10}\)
<=> \(\frac{47}{28}.x=\frac{7}{10}\)
<=> \(x=\frac{98}{235}\)
\(\left(x-\frac{1}{2}\right).\frac{5}{3}=\frac{7}{4}-\frac{1}{2}\)
<=> \(\left(x-\frac{1}{2}\right).\frac{5}{3}=\frac{5}{4}\)
<=> \(x-\frac{1}{2}=\frac{3}{4}\)
<=> \(x=\frac{5}{4}\)
học tốt
1. a\()\) \(\frac{9}{4}\)\(-\) \(\frac{3}{4}\) \(\times\) \(\frac{1}{5}\)
= \(\frac{9}{4}\) \(-\) \(\frac{3}{20}\)
= \(\frac{45}{20}\) \(-\) \(\frac{3}{20}\)
= \(\frac{21}{10}\)
b\()\) \(\frac{2}{5}\) \(\times\) \(\frac{1}{3}\) \(\times\) \(\frac{3}{5}\)
= \(\frac{2}{15}\) \(\times\) \(\frac{3}{5}\)
= \(\frac{2}{25}\)
2.
a\()\) câu a mik vẫn chưa hiểu đề là gì
b\()\) \(\frac{7}{5}\) \(\div\) x \(=\) \(\frac{2}{3}\) \(\times\) \(\frac{1}{4}\)
\(\frac{7}{5}\) \(\div\) x \(=\) \(\frac{1}{6}\)
x \(=\) \(\frac{7}{5}\) \(\div\) \(\frac{1}{6}\)
x \(=\) \(\frac{7\times6}{5\times1}\)
x \(=\) \(\frac{42}{5}\)
Bài 2:
a: =>3/4x=-3/5-1/2=-11/10
\(\Leftrightarrow x=\dfrac{-11}{10}:\dfrac{3}{4}=\dfrac{-11}{10}\cdot\dfrac{4}{3}=-\dfrac{44}{30}=-\dfrac{22}{15}\)
b: \(\Leftrightarrow x+\dfrac{3}{4}x=\dfrac{1}{3}+\dfrac{5}{4}=\dfrac{19}{12}\)
=>7/4x=19/12
=>x=19/21
c: \(\Leftrightarrow-\dfrac{2}{3}x+\dfrac{1}{6}=\dfrac{2}{3}x-\dfrac{1}{3}\)
=>-4/3x=-1/3-1/6=-1/2
=>x=1/2:4/3=1/2x3/4=3/8
Bài 1
\(\dfrac{1}{7}:\dfrac{5}{17}-\dfrac{3}{2}.\left(\dfrac{1}{6}-\dfrac{7}{12}\right)\)
\(\dfrac{1}{7}.\dfrac{17}{5}-\dfrac{3}{2}.\left(-\dfrac{5}{12}\right)\)
\(\dfrac{17}{35}-\left(-\dfrac{5}{8}\right)\)
\(\dfrac{17}{35}+\dfrac{5}{8}\)
\(\dfrac{311}{280}\)
a) \(\frac{3}{2}x-\frac{2}{5}=\frac{1}{3}x-\frac{1}{4}\)
\(\Rightarrow\frac{3}{2}x-\frac{1}{3}x=-\frac{1}{4}+\frac{2}{5}\)
\(\frac{7}{6}x=\frac{3}{20}\Rightarrow x=\frac{9}{70}\)
b) \(-5^{\frac{1}{2}x+1}=\frac{3}{4}-\frac{7}{6}\)
\(-5^{\frac{1}{2}x}.\left(-5\right)=-\frac{5}{12}\)
\(-5^{\frac{1}{2}x}=\frac{1}{12}\)
mà -51/2x mang giá trị âm
1/12 có giá trị dương
=> không tìm được x
c) \(\frac{2x-2}{3}=\frac{7x+3}{2-1}\)
\(\frac{2x-2}{3}=7x+3=\frac{21x+9}{3}\)
=> 2x - 2 = 21x + 9
=> 2x - 21x = 9 + 2
-19x = 11
x = -11/19
phần d bn lm như phần a nha
\(\dfrac{3}{4}+\dfrac{1}{4}:x-\dfrac{1}{2}=\dfrac{2}{3}\\ \dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{3}+\dfrac{1}{2}=\dfrac{7}{6}\\ \dfrac{1}{4}:x=\dfrac{7}{6}-\dfrac{3}{4}\\ \dfrac{1}{4}:x=\dfrac{5}{12}\\ x=\dfrac{1}{4}:\dfrac{5}{12}\\ x=\dfrac{1}{4}\cdot\dfrac{12}{5}=\dfrac{3}{5}\)