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a) \(\left(x+\frac{7}{4}\right)\times\frac{3}{2}=6\)
\(\Leftrightarrow\left(x+\frac{7}{4}\right)=6\div\frac{3}{2}\)
\(\Leftrightarrow x+\frac{7}{4}=4\)
\(\Leftrightarrow x=4-\frac{7}{4}\)
\(\Leftrightarrow x=\frac{9}{4}\)
b) \(x\div\frac{3}{5}+\frac{2}{5}=\frac{9}{5}\)
\(\Leftrightarrow x\div\frac{3}{5}=\frac{9}{5}-\frac{2}{5}\)
\(\Leftrightarrow x\div\frac{3}{5}=\frac{7}{5}\)
\(\Leftrightarrow x=\frac{7}{5}\times\frac{3}{5}\)
\(\Leftrightarrow x=\frac{21}{25}\)
c) \(\frac{1}{2}\div3+x=\frac{5}{3}\)
\(\Leftrightarrow\frac{1}{6}+x=\frac{5}{3}\)
\(\Leftrightarrow x=\frac{5}{3}-\frac{1}{6}\)
\(\Leftrightarrow x=\frac{3}{2}\)
x x - 4/7 = 15/20
(hình như sai đề, tại vì lớp 4 chưa học lũy thừa)
x * 2/7 -2/3 =1/2
x* 2/7 = 1/2 + 2/3
x* 2/7 = 7/6
x= 7/6 : 2/7
x= 49/12
x : 5/4 + 4/5 =2
x: 5/4 = 2 - 4/5
x: 5/4 = 6/5
x= 6/5 * 5/4
x= 3/2
4/3 x 7/8 x 5
= 7/6 x 5
= 35/6
8/9 x 6/5 x 2/3
= 16/15 x 2/3
= 32/45
4/7 : 5/7 x 10/11
= 4/5 x 10/11
= 8/11
8/13 : 7/13 : 4
= 8/7 : 4
= 2/7
\(A=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}\)
= \(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}\)
= \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\)
= \(1-\frac{1}{7}\)
= \(\frac{7}{7}-\frac{1}{7}\)
= \(\frac{6}{7}\)
2) \(\frac{7}{4}-x.\frac{4}{3}=\frac{5}{19}\)
\(x.\frac{4}{3}=\frac{7}{4}-\frac{5}{19}\)
\(x.\frac{4}{3}=\frac{133}{76}-\frac{20}{76}\)
\(x.\frac{4}{3}=\frac{113}{76}\)
\(x=\frac{113}{76}:\frac{4}{3}\)
\(x=\frac{399}{304}\)
VẬY \(x=\frac{399}{304}\)
b) \(\left(x+\frac{3}{4}\right).\frac{5}{7}=\frac{10}{9}\)
\(\left(x+\frac{3}{4}\right)=\frac{10}{9}:\frac{5}{7}\)
\(x+\frac{3}{4}=\frac{14}{9}\)
\(x=\frac{14}{9}-\frac{3}{4}\)
\(x=\frac{29}{36}\)
Vậy \(x=\frac{29}{36}\)
c) \(x.\frac{1}{2}+\frac{3}{2}.x=\frac{4}{5}\)
\(x.\left(\frac{1}{2}+\frac{3}{2}\right)=\frac{4}{5}\)
\(x.2=\frac{4}{5}\)
\(x=\frac{4}{5}:2\)
\(x=\frac{2}{5}\)
Vậy \(x=\frac{2}{5}\)
Chúc bạn học tốt !!!
a] 4/12 ; 5/12 ; 11/2 ; 1/4
b] 1 ; 9/12; 12/5 ; 11/3
c] 8/21; 6/11;8/7
d] 2/3 ;2/7 15/2
a]1/3 5/12 11/2 1/4
b]1 3/4 12/5 33/9
c]8/21 6/11 8/7
d]2/3 2/7 15/2
a: =5/6(1/8+2/3)=5/6*19/24=95/144
b: =3/4(7/5-1/2)=27/40
c: =35/24*2/3=35/36
a\()\) 1/2 x 2/3 : 5/6 x 5/6
=2/6 : 35/36
=1/3 x 36/35
=36/105=12/35
b\()\)11x15x56/6x35x38
=165x56/6x35x38
=9240/6x35x38
=1540x35x38
=53900x38
=2,048,200
c\()\) 2/7 x 7/5 + 2/7 - 2/7 x 6/5
=2/7x\(\left(\dfrac{7}{5}-\dfrac{2}{7}\right)\)+2/7
=2/7 x 39/35 + 2/7
=2/7 x \(\left(\dfrac{39}{35}+1\right)\)
=2/7 x 74
=148/7
Bài 1 :
a) \(\left(\frac{6}{5}+7\right)\times9\)
\(=\frac{6}{5}\times9+7\times9\)
\(=\frac{54}{5}+63\)
\(=\frac{369}{5}\)
b) \(\frac{7}{4}\times8+\frac{7}{4}\times2\)
\(=\frac{7}{4}\times\left(8+2\right)\)
\(=\frac{7}{4}\times10\)
\(=\frac{35}{2}\)
Bài 2 :
a) \(x:\frac{1}{4}=6\)
\(x=6\times\frac{1}{4}\)
\(x=\frac{3}{2}\)
b) \(\frac{1}{4}:x=6\)
\(x=\frac{1}{4}:6\)
\(x=\frac{1}{24}\)
c) \(\frac{1\times2\times3\times4}{5\times6\times7\times8}\times x=1\)
\(\frac{1}{70}\times x=1\)
\(x=1:\frac{1}{70}\)
\(x=70\)
d) \(x\times\frac{3}{4}+2=3\)
\(x\times\frac{3}{4}=3-2\)
\(x\times\frac{3}{4}=1\)
\(x=1:\frac{3}{4}\)
\(x=\frac{4}{3}\)
e) \(x:\frac{7}{5}-1=6\)
\(x:\frac{7}{5}=6+1\)
\(x:\frac{7}{5}=7\)
\(x=7\times\frac{7}{5}\)
\(x=\frac{49}{5}\)
g) \(x:\frac{7}{5}\times8=8\)
\(x:\frac{7}{5}=8:8\)
\(x:\frac{7}{5}=1\)
\(x=1\times\frac{7}{5}\)
\(x=\frac{7}{5}\)
Bài 3 :
a) Phân số chỉ phần chưa đọc là :
\(1-\frac{1}{3}-\frac{2}{5}=\frac{4}{15}\)( quyển sách )
b) Số trang bạn Ngọc chưa đọc là :
\(450\times\frac{4}{15}=120\)( trang )
Đáp số : a) \(\frac{4}{15}\)quyển sách
: b) 120 trang
Học tốt #
a,7.x-8=6
x-8=6:7
x-8=6/7
x=6/7+8
x=62/7
Vậy x=62/7
b, 8.(x-5)=0
x-5=0:8
x-5=0
x=0+5
x=5
Vậy x = 5
c, x -6:2-(48-24.2:6-3)=0
x-6:2-(48-48:6-3)=0
x-6:2-(48-8-3)=0
x-6:2-(40-3)=0
x-6:2-37=0
x-6:2=0+37
x-3=37
x=37+3
x=40
Vẫy=40
2/5 + 4/7 : x = 3
4/7 : x = 3 - 2/5
4/7 : x = 13/5
x = 4/7 : 13/5
x = 20/91
Câu 2 :
5/6 - x : 2/3 = 1/2
x : 2/3 = 5/6 - 1/2
x : 2/3 = 1/3
x = 1/3 x 2/3
x = 2/9
lấy 3 trừ 2/5 rồi lấy kết quả chia 4/7 câu 1
câu 2 bạn viết chẳng hiểu gì cả