100%:x-70%:x+40%:x-1/4:x=0,81
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\(a,25\%x=42,6-3,28\\ \Leftrightarrow\dfrac{1}{4}x=39,32\\ \Leftrightarrow x=157,28\)
\(b,x:40\%=7,25+6,75\\ \Leftrightarrow x:40\%=14\\ \Leftrightarrow x=5,6\)
\(c,\dfrac{7011}{25}:\left(x-42,6\right)=117,14-47,03\\ \Leftrightarrow\dfrac{7011}{25}:\left(x-42,6\right)=70,11\\ \Leftrightarrow x-42,6=4\\ \Leftrightarrow x=46,6\)
\(d,0,3\left(x+\dfrac{1}{3}\right)=\dfrac{1}{2}\cdot\left(0,81:27\right)\\ \Leftrightarrow0,3\left(x+\dfrac{1}{3}\right)=0,015\\ \Leftrightarrow x+\dfrac{1}{3}=0,05\\ \Leftrightarrow x=-\dfrac{17}{60}\)
a) (x+1)+(x+2)+(x+3)+...+(x+100)
=100.x+(1+2+3,..+100)
=100.x+100.101/2
=>
100x+101.50=5750
100x=5750-5050=700
x=7
b) 433 - (15x + 70) = 33
(15x + 70) = 433 - 33
(15x + 70) = 400
15x = 400 - 70
15x = 330
x = 330 : 15
x = 22
c) (13 + x ) . 8 = 136
(13 + x ) = 136 : 8
(13 + x ) = 17
x = 17 - 13
x = 4
d) 3x - 35 = 40
3x = 40 + 35
3x = 75
x = 75 : 3
x = 25
các bạn ơi hãy k cho mk và kban các bạn nhé!!!! I love you!!!! thank for reading. chúc các bạn học giỏi
( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ... + ( x + 100 ) = 5750
x x 100 + ( 1 + 2 + 3 + ... + 100 ) = 5750
x x 100 + 5050 = 5750
x x 100 = 5750 - 5050
x x 100 = 700
x = 700 : 100
x = 7
Mấy cái dưới dễ tự làm ik chứ bn
1)\(\frac{x+1}{2}+\frac{x+1}{3}+\frac{x+1}{4}=\frac{x+1}{5}+\frac{x+1}{6}\)
\(\Leftrightarrow\frac{x+1}{2}+\frac{x+1}{3}+\frac{x+1}{4}-\frac{x+1}{5}-\frac{x+1}{6}=0\)
\(\Leftrightarrow\left(x+1\right)\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}-\frac{1}{5}-\frac{1}{6}\right)=0\)
\(\Leftrightarrow\left(x+1\right)=0\).Do \(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}-\frac{1}{5}-\frac{1}{6}\ne0\)
\(\Leftrightarrow x=-1\)
a)\(\frac{x+7}{x}=\frac{4}{5}\)
=>5(x+7)=4x
5x+35=4x
5x-4x=-35
x=-35
Vậy x=-35
b)(x-20)/(x+40)=(x+70)/(x-10)
(x-20)*(x-10)=(x+40)*(x+70)
x(x-10)-20(x-10)=x(x+70)+40(x+70)
x2-10x-20x+200=x2+70x+40x+2800
x2-x2-10x-20x-70x-40x=2800-200
0-(10x+20x+70x+40x)=2600
-140x=2600
x=2600/(-140)
x=\(-\frac{130}{7}\)
Vậy x=-130/7
100%:x-70%:x+40%:x-1/4:x=0,81
=>(1-7/10+4/10-1/4) / x= 0,81
=>9/20 : x=81/100
=>x=81/100 x 20/9
=>x=9/5
\(100\%:x-70\%:x+40\%:x-\frac{1}{4}:x=0,81.\)
\(=1:x-\frac{7}{10}:x+\frac{2}{5}:x-\frac{1}{4}:x=\frac{81}{100}\)
\(\left(1-\frac{7}{10}+\frac{2}{5}-\frac{1}{4}\right):x=\frac{81}{100}\)
\(\frac{9}{20}:x=\frac{81}{100}\)
\(x=\frac{9}{20}:\frac{81}{100}\)
\(x=\frac{5}{9}\)