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(x+5/3).9/13=2/3
x+5/3=2/3:9/13
x+5/3=2/3.9/13
x+5/3=26/27
x=26/27-5/3
x=26/27-45/27
vô lí vì 26 ko trừ đc cho 45
vậy x ko có gtri thỏa mãn
hoặc làm theo cách cấp 2 thì 26-45=-19
chúc bạn học tốt
1.
=3/5x(3/7+4/7)+2/5x(13/9-4/9)
=3/5x1+2/5x1
=3/5+2/5
=1
2.Xx(3/4+4/5)=7/10
Xx31/20=7/10
X =7/10:31/20
X =14/31
\(\frac{3}{5}\cdot\frac{3}{7}+\frac{3}{5}\cdot\frac{4}{7}+\frac{2}{5}\cdot\frac{13}{9}-\frac{2}{5}\cdot\frac{4}{9}\)
\(=\frac{3}{5}\cdot\left(\frac{3}{7}+\frac{4}{7}\right)+\frac{2}{5}\cdot\left(\frac{13}{9}-\frac{4}{9}\right)\)
\(=\frac{3}{5}\cdot1+\frac{2}{5}\cdot1\)\(=\frac{3}{5}+\frac{2}{5}=1\)
_________________________________________
\(\frac{3}{4}\cdot x+\frac{4}{5}\cdot x=\frac{7}{10}\)
\(\left(\frac{3}{4}+\frac{4}{5}\right)\cdot x=\frac{7}{10}\)
\(\frac{31}{20}\cdot x=\frac{7}{10}\)
\(x=\frac{7}{10}:\frac{31}{20}\)
\(x=\frac{14}{31}\)
\(x+\frac{3+\frac{3}{20}+\frac{3}{13}+\frac{3}{2013}}{5+\frac{5}{20}+\frac{5}{13}+\frac{5}{2013}}=\frac{9}{2}\)
\(x+\frac{3\times\left(1+\frac{1}{20}+\frac{1}{13}+\frac{1}{2013}\right)}{5\times\left(1+\frac{1}{20}+\frac{1}{13}+\frac{1}{2013}\right)}=\frac{9}{2}\)
\(x+\frac{3}{5}=\frac{9}{2}\)
\(x=\frac{39}{10}\)
\(x=3,9\)
a) 3/5x7/9+11/9x3/5
=3/5 x(7/9+11/9)
= 3/5x2
=6/5
b)14/13:1/2+3/13x2-2x7/13
= 14/13 x 2 +3/13 x2 - 2x7/13
=2 x (14/13 +3/13 -7/13)
= 2 x 10/13
= 20/13
a) 3/5 x 7/9 + 11/9 x 3/5 - 3/10
= 3/5 x 7/9 + 11/9 x 3/5 - 3/5 x 2
= 3/5 x ( 7/9 + 11/9 - 2 )
= 3/5 x 0
= 0
b) 14/13 : 1/2 + 3/13 x 2 - 2 x 7/13
= 14/13 x 2/1 + 3/13 x 2 - 2 x 7/13
= ( 14/13 + 3/13 - 7/13 ) x 2
= 10/13 x 2 = 20/13
1.
7/15:(1/2-9/10xX)-1/6=13/6
=>7/15:(1/2-9/10xX)=13/6+1/6
=>7/16:(1/2-9/10xX)=7/3
=>1/2-9/10xX=7/16:7/3
=>1/2-9/10xX=3/16
=>9/10xX=1/2-3/16
=>9/10xX=5/16
=>X=5/16:9/10
=>X=25/72
a) \(\frac{2}{5}\)+ X = \(\frac{13}{15}\) - \(\frac{1}{3}\)
\(\frac{2}{5}+X=\frac{8}{15}\)
\(X=\frac{8}{15}-\frac{2}{5}\)
\(X=\frac{2}{15}\)
a) 2/5 + x = 13/15 - 1/3
2/5 + x = 8/15
x = 8/15 - 2/5
x = 2/15
b) x - 2/9 = 2/3 x 2
x - 2/9 = 4/3
x = 4/3 + 2/9
x = 14/9
1) (x - 35) - 120 = 0
x - 35 = 120
x = 120 + 35
x = 155
2) 310 - (118 - x) = 217
118 - x = 310 - 217
118 - x = 93
x = 118 - 93
x = 25
3) 156 - (x + 61) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
4) 814 - (x - 305) = 712
x - 305 = 814 - 712
x - 305 = 102
x = 102 + 305 = 407
5) 100 - 7 - (x - 5) = 58
x - 5 = 93 - 58
x - 5 = 35
x = 35 + 5 = 40
6) 12(x - 1) : 3 = 43 + 23
4(x - 1) = 72
x - 1 = 18
x = 18 + 1 = 19
7) 24 + 5x = 75 : 73
24 + 5x = 49
5x = 25
x = 25 : 5 = 5
8) 5(x - 1) : 3 = 43 + 23
\(\dfrac{5}{3}\left(x-1\right)=72\)
x - 1 = \(\dfrac{216}{5}\)
x = 221/5
9) 5(x - 4)2 - 7 = 13
5(x - 4)2 = 20
(x - 4)2 = 4
\(\Rightarrow\left[{}\begin{matrix}x-4=2\\x-4=-2\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=6\\x=2\end{matrix}\right.\)
10) (x + 1) + (x + 2) + ... + (x + 30) = 795
=> (x + x + x + ... + x) + (1 + 2 + 3 +...+ 30) = 795 (1)
Đặt A = 1 + 2 + 3 +...+ 30
Số số hạng trong A là: (30 - 1) : 1 + 1 = 30 (số)
Tổng A bằng : (30 + 1).30 : 2 =465
Thay A = 465 vào (1) , ta được:
30x + 465 = 795
=> 30x =330
=> x =11
1: =>x-35=120
=>x=120+35=155
2: =>118-x=310-217=93
=>x=118-93=25
3: =>x+61=156-82=74
=>x=74-61=13
4: =>x-305=814-712=102
=>x=102+305=407
5: =>93-(x-5)=58
=>x-5=35
=>x=40
6: =>4(x-1)=64+8=72
=>x-1=18
=>x=19
7: =>5x+24=49
=>5x=25
=>x=5
8: =>5(x-1):3=4^3+2^3=64+8=72
=>5(x-1)=216
=>x-1=216/5
=>x=221/5
( x + 1 ) + ( x + 3 ) + ( x + 5 ) + ( x + 7 ) + ( x + 9 ) + ( x + 11 ) + ( x + 13 ) = 119
( x + x + x + x + x + x + x ) + ( 1 + 3 + 5 + 7 + 9 + 11 + 13 ) = 119
7x + 49 = 119
7x = 119 - 49
7x = 70
x = 70 : 7
x = 10
\((x+3/5)\times9/13=2/3\)
`x+3/5=2/3:9/13`
\(x+3/5=2/3\times13/9\)
`x+3/5=26/27`
`x=26/27-3/5=49/135`
x = 49/135