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\(a.\)
\(\frac{4}{9}.x=\frac{1}{9}\)
\(\Rightarrow x=\frac{1}{9}:\frac{4}{9}\)
\(\Rightarrow x=\frac{1}{9}.\frac{9}{4}\)
\(\Rightarrow x=\frac{1}{4}\)
Vậy \(x=\frac{1}{4}\)
\(b.\)
\(\frac{7}{18}.x-\frac{2}{3}=\frac{5}{18}\)
\(\Rightarrow\frac{7}{18}.x=\frac{5}{18}+\frac{2}{3}\)
\(\Rightarrow\frac{7}{18}.x=\frac{5}{18}+\frac{12}{18}\)
\(\Rightarrow\frac{7}{18}.x=\frac{17}{18}\)
\(\Rightarrow x=\frac{17}{18}:\frac{7}{18}\)
\(\Rightarrow x=\frac{17}{18}.\frac{18}{7}\)
\(\Rightarrow x=\frac{17}{7}\)
Vậy \(x=\frac{17}{7}\)
\(c.\)
\(x:-\frac{1}{12}=\frac{7}{12}\)
\(\Rightarrow x=\frac{7}{12}.-\frac{1}{12}\)
\(\Rightarrow x=-\frac{7}{144}\)
Vậy \(x=-\frac{7}{144}\)
\(d.\)
\(\frac{4}{9}-\frac{7}{8}.x=-\frac{2}{3}\)
\(\Rightarrow\frac{7}{8}.x=\frac{4}{9}-\left(-\frac{2}{3}\right)\)
\(\Rightarrow\frac{7}{8}.x=\frac{4}{9}+\frac{2}{3}\)
\(\Rightarrow\frac{7}{8}.x=\frac{4}{9}+\frac{6}{9}\)
\(\Rightarrow\frac{7}{8}.x=\frac{10}{9}\)
\(\Rightarrow x=\frac{10}{9}:\frac{7}{8}\)
\(\Rightarrow x=\frac{10}{9}.\frac{8}{7}\)
\(\Rightarrow x=\frac{80}{63}\)
Vây \(x=\frac{80}{63}\)
\(e.\)
\(-\frac{5}{14}:x=-\frac{3}{10}\)
\(\Rightarrow x=-\frac{5}{14}:-\frac{3}{10}\)
\(\Rightarrow x=-\frac{5}{14}.-\frac{10}{3}\)
\(\Rightarrow x=\frac{5}{7}.\frac{5}{3}\)
\(\Rightarrow x=\frac{25}{21}\)
Vậy \(x=\frac{25}{21}\)
\(g.\)
\(\frac{1}{6}+\frac{-5}{7}:x=-\frac{7}{18}\)
\(\Rightarrow-\frac{5}{7}:x=-\frac{7}{18}-\frac{1}{6}\)
\(\Rightarrow-\frac{5}{7}:x=-\frac{7}{18}-\frac{3}{18}\)
\(\Rightarrow-\frac{5}{7}:x=-\frac{10}{18}\)
\(\Rightarrow-\frac{5}{7}:x=-\frac{5}{9}\)
\(\Rightarrow x=-\frac{5}{7}:-\frac{5}{9}\)
\(\Rightarrow x=-\frac{5}{7}.-\frac{9}{5}\)
\(\Rightarrow x=\frac{9}{7}\)
Vậy \(x=\frac{9}{7}\)
-37 + 14 +26 + 37
=-37 + 37 + 14 + 36
=0 + 50
=50
-24 + 6 + 10 + 24
=(-24 + 24) +(6+10)
= 0+16
= 16
|Câu d:
x = 3/4 + 1/-12
x = 9/12 - 1/12
x = 8/12
x = 2/3
Vậy x = 2/3
Câu e:
x /14 = 1/7 + (-3)/14
x/14 = 1/7 - 3/14
x/14 = 2/14 - 3/14
x/14 = -1/14
x = - 1/14 x 14
x = -1
Vậy x = -1
Bài 1:
1; ( - 35) : (-7) = 5
2; (- 42) : 21 = - 2
3; 45 : (-9) = -5
4; 18 : 9 = 2
5; (- 30) : (- 15) = 2
6; 0 : 18 = 0
7; 0 : (-13) = 0
8; 44 : (-4) = - 11
9; - 55 : 11 = - 5
10; 46 : 23 = 2
a) \(\frac{2}{5}+x=\frac{3}{4}\)
\(x=\frac{3}{4}-\frac{2}{5}\)
\(x=\frac{15}{20}-\frac{8}{20}\)
\(x=\frac{7}{20}\)
\(\)b)
\(x-\frac{1}{15}=\frac{3}{10}\\ x=\frac{3}{10}+\frac{1}{15}\\ x=\frac{9}{30}+\frac{2}{30}\\ x=\frac{11}{30}\)
c)
\(\frac{9}{8}-x=\frac{5}{12}\\ x=\frac{9}{8}-\frac{5}{12}\\ x=\frac{27}{24}-\frac{10}{24}\\ x=\frac{17}{24}\)
d)
\(\frac{3}{5}+x=\frac{5}{4}+\frac{7}{10}\\ \frac{3}{5}+x=\frac{25}{20}+\frac{14}{20}\\\frac{3}{5}+x=\frac{39}{20}\\ x=\frac{39}{20}-\frac{3}{5}\\ x=\frac{39}{20}-\frac{12}{20}\\ x=\frac{27}{20} \)
e)
\(\frac{9}{8}-x=\frac{3}{20}+\frac{2}{5}\\ \frac{9}{8}-x=\frac{3}{20}+\frac{8}{20}\\ \frac{9}{8}-x=\frac{11}{20}\\ x=\frac{9}{8}-\frac{11}{20}\\ x=\frac{45}{40}-\frac{22}{40}\\ x=\frac{23}{40}\)
g)
\(x+\frac{1}{3}=\frac{5}{6}+1\frac{7}{10}\\ x+\frac{1}{3}=\frac{5}{6}+\frac{17}{10}\\ x+\frac{1}{3}=\frac{25}{30}+\frac{51}{30}\\ x+\frac{1}{3}=\frac{76}{30}=\frac{38}{15}\\ x=\frac{38}{15}-\frac{1}{3}\\ x=\frac{38}{15}-\frac{5}{15}\\ x=\frac{33}{15}=\frac{11}{5}\)
h)
\(3x-\frac{3}{5}=\frac{1}{2}\\ 3x=\frac{1}{2}+\frac{3}{5}\\ 3x=\frac{5}{10}+\frac{6}{10}\\ 3x=\frac{11}{10}\\ x=\frac{11}{10}:3\\ x=\frac{11}{10}\cdot\frac{1}{3}\\ x=\frac{11}{30}\)
i)
\(4x+\frac{5}{12}+\frac{4}{9}=1\frac{13}{18}\\ 4x+\frac{5}{12}+\frac{4}{9}=\frac{31}{18}\\ 4x+\frac{5}{12}=\frac{31}{18}-\frac{4}{9}\\ 4x+\frac{5}{12}=\frac{31}{18}-\frac{8}{18}\\ 4x+\frac{5}{12}=\frac{23}{18}\\ 4x=\frac{23}{18}-\frac{5}{12}\\ 4x=\frac{46}{36}-\frac{15}{36}\\ 4x=\frac{31}{36}\\ x=\frac{31}{36}:4\\ x=\frac{31}{36}\cdot\frac{1}{4}\\ x=\frac{31}{144}\)
k)
\(2-\left(3x+\frac{3}{7}\right)=\frac{9}{21}\\ 2-\left(3x+\frac{3}{7}\right)=\frac{3}{7}\\3x+\frac{3}{7}=2-\frac{3}{7}\\ 3x+\frac{3}{7}=\frac{14}{7}-\frac{3}{7}\\ 3x+\frac{3}{7}=\frac{11}{7}\\ 3x=\frac{11}{7}-\frac{3}{7}\\ 3x=\frac{8}{7}\\ x=\frac{8}{7}:3\\ x=\frac{8}{7}\cdot\frac{1}{3}\\ x=\frac{8}{21} \)
1/(2.x-5)+17=6
=> 2x - 5 = -11
=> 2x = -6
=> x = 3
vậy_
2/10-2.(4-3x)=-4
=> 2(4 - 3x) = 14
=> 4 - 3x = 7
=> 3x = -3
=> x = -1
3/-12+3.(-x+7)=-18
=> 3(-x+7) = -6
=> -x+7 = -2
=> -x = -9
=> x = 9
4/24:(3.x-2)=-3
=> 3x - 2 = -8
=> 3x = -6
=> x = -2
5/-45:5.(-3-2.x)=3
=> 5(-3 - 2x) = -15
=> -3 - 2x = -3
=> - 2x = 0
=> x = 0
6/x.(x+7)=0
=> x = 0 hoặc x + 7 = 0
=> x = 0 hoặc x = -7
7/(x+12).(x-3)=0
=> x + 12 = 0 hoặc x - 3 = 0
=> x = -12 hoặc x = 3
8/(-x+5).(3-x)=0
=> -x + 5 = 0 hoặc 3 - x = 0
=> x = 5 hoặc x = 3
9/x.(2+x).(7-x)=0
=> x = 0 hoặc 2 + x = 0 hoặc 7 - x = 0
=> x = 0 hoặc x = -2 hoặc x = 7
10/(x-1).(x+2).(-x-3)=0
=> x - 1 = 0 hoặc x + 2 = 0 hoặc -x-3 = 0
=> x = 1 hoặc x = -2 hoặc x = -3
Câu 1:
a; x/7 = - 9/14
x = - 9/14 x 7
x = - 9/2
Vậy x = -9/2
b; - 16/36 = - y/4
-4/9 = - y/4
y = -4/9 x (-4)
y = 16/9
Vậy y = 16/9
Câu 1c:
-5/12 = x/60
x = -5/12 x 60
x = - 25
Vậy x = - 25
d: -4/8 = x/-10 = -7/y
-4/8 = x/-10
x = -4/8 x (-10)
x = 5
-4/8 = -7/y
y = - 7 : (-4/8)
y = 7 x 8/4
y = 14
Vậy (x; y) = (5; 14)
a) x= 1/4
b) x= -7/144
c) x= 25/6
d) x=17/7
e) x= 80/63
f) x= -45/14
Câu a:
4/9.x = 1/9
x = 1/9 : 4/9
x = 1/9 x 9/4
x = 1/4
vậy x = 1/4
Câu b:
x : -1/2 = 7/12
x = 7/12 x (-1/2)
x = - 7/24
Vậy x = - 7/24
Câu c:
-5/4 : x = -3/10
x = -5/4 : (-3/10)
x = -5/4 x (-10/3)
x = 25/6
Vậy x = 25/6
Câu d:
7/18.x - 2/3 = 5/18
7/18x = 5/18 + 2/3
7/18x = 5/18 + 12/18
7/18x = 17/18
x = 17/18 : 7/18
x = 17/18 x 18/7
x = 17/7
Vậy x = 17/7
câu e;
4/9 - 7/8x = -2/3
7/8x = 4/9 + 2/3
7/8x = 4/9 + 6/9
7/8x = 10/9
x = 10/9 : 7/8
x = 10/9 x 8/7
x = 80/63
Vậy x = 80/63
Câu f:
1/6 - 5/7 : x = - 7/18
5/7 : x = 1/6 + 7/18
5/7 : x = 3/18 + 7/18
5/7 : x = 5/9
x = 5/7 : 5/9
x = 5/7 x 9/5
x = 9/7
Vậy x = 9/7