3200:(+3xX)=4
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3x/4 + 3x/28 + 3x/70 + ... + 3x/304 = 18/19
=> x(3/1*4 + 3/4*7 + 3/7*10 + ... + 3/16*19) = 18/19
=> x(1 - 1/4 + 1/4 - 1/7 + 1/7 - 1/10 + ... + 1/16 - 1/19) = 18/19
=> x(1 - 1/19) = 18/19
=> x*18/19 = 18/19
=> x = 1
\(3.\frac{x}{4}+3.\frac{x}{28}+3.\frac{x}{70}+...+3.\frac{x}{304}=\frac{18}{19}\)
\(3.\left(\frac{x}{4}+\frac{x}{28}+\frac{x}{70}+...+\frac{x}{304}\right)\)
\(\frac{x}{4}+\frac{x}{28}+\frac{x}{70}+...+\frac{x}{304}=\frac{18}{19}:3=\frac{6}{19}\)
Nhân hai vế với 3/x ta được
\(\frac{3}{x}\left(\frac{x}{4}+\frac{x}{28}+\frac{x}{70}+...+\frac{x}{304}\right)=\frac{6}{19}.\frac{3}{x}\)
\(\frac{3}{x}.\frac{x}{4}+\frac{3}{x}.\frac{x}{28}+\frac{3}{x}.\frac{x}{70}+...+\frac{3}{x}.\frac{x}{304}=\frac{18}{19.x}\)
\(\frac{3}{4}+\frac{3}{28}+\frac{3}{70}+...+\frac{3}{304}=\frac{18}{19}:x\)
\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{16.19}=\frac{18}{19}:x\)
\(1-\frac{1}{19}=\frac{18}{19}:x\)
\(\frac{18}{19}=\frac{18}{19}:x\)
\(x=\frac{18}{19}:\frac{18}{19}=1\)
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P/s: Không hiểu chỗ nào cứ ib
\(\left(3\times x-4\right):2+\frac{1}{4}=\frac{3}{4}\)
\(\left(3\times x-4\right):2=\frac{3}{4}-\frac{1}{4}\)
\(\left(3\times x-4\right):2=\frac{1}{2}\)
\(\left(3\times x-4\right)=\frac{1}{2}\times2\)
\(3\times x-4=1\)
\(3\times x=1+4\)
\(3\times x=5\)
\(x=5:3\)
\(x=\frac{5}{3}\)
2.(4 - 3.x) + 15 = 23
2.(4 - 3.x) = 23 - 15
2.(4 - 3.x) = 8
4 - 3.x = 8 : 2
4 - 3.x = 4
3.x = 4 - 4
3.x = 0
x = 0 : 3
x = 0
Vậy x = 0
2x(4-3xX)+15=23
2x(4-3xX)=23-15=8
(4-3xX)=8:2=4
3xX=4-4=0
X=0:3=0
Đáp án: X=0
`@` `\text {Ans}`
`\downarrow`
\(\dfrac{2}{3}\times x-\dfrac{x}{2}-\dfrac{1}{2}=\dfrac{1}{4}?\)
`=>`\(\dfrac{2}{3}x-\dfrac{x}{2}-\dfrac{1}{2}=\dfrac{1}{4}\)
`=>`\(\dfrac{4x}{6}-\dfrac{3x}{6}-\dfrac{1}{2}=\dfrac{1}{4}\)
`=>`\(\dfrac{x}{6}-\dfrac{1}{2}=\dfrac{1}{4}\)
`=>`\(\dfrac{x}{6}=\dfrac{1}{4}+\dfrac{1}{2}\)
`=>`\(\dfrac{x}{6}=\dfrac{3}{4}\)
`=> 4x=3*6`
`=> 4x=18`
`=> x=`\(\dfrac{18}{4}=\dfrac{9}{2}=4,5\)
Vậy, `x=4,5.`
\(\href{https://hoc24.vn/vip/14874167551162}{\text{_KaizulvG_}}\)
1/2 * x + 2/3 * x = x + 4
x * (1/2+2/3) = x + 4
7/6 * x = x + 4
7/6 * x - x = 4
1/6 * x = 4
x = 24
50%.x+2/3.x=x+4
=>1/2.x+2/3.x=x+4
(1/2+2/3).x=x+4
7/6.x=x+4
x+4:x=7/6
ae cầu cứu tau làm saI RỒI @@
\(\dfrac{1}{4}+\dfrac{1}{3}\times X=\dfrac{1}{2}\\ \dfrac{1}{3}\times X=\dfrac{1}{2}-\dfrac{1}{4}=\dfrac{1}{4}\\ X=\dfrac{1}{4}:\dfrac{1}{3}=\dfrac{1}{4}\times3=\dfrac{3}{4}\)
14+13×�=1213×�=12−14=14�=14:13=14×3=3441+31×X=2131×X=21−41=41X=41:31=41×3=43
a. \(\dfrac{5}{7}+\dfrac{4}{3}:x=\dfrac{1}{7}\)
<=> \(\dfrac{5}{7}+\dfrac{4}{3}.\dfrac{1}{x}=\dfrac{1}{7}\)
<=> \(\dfrac{5}{7}+\dfrac{4}{3x}=\dfrac{1}{7}\) ĐKXĐ: x \(\ne\) 0
<=> \(\dfrac{15x}{21x}+\dfrac{28}{21x}=\dfrac{3x}{21x}\)
<=> 15x + 28 = 3x
<=> 15x - 3x = -28
<=> 12x = -28
<=> x = \(\dfrac{-28}{12}=-\dfrac{7}{3}\)
b. \(\dfrac{5}{3}x.\dfrac{-1}{4}=\dfrac{2}{6}\)
<=> \(\dfrac{-5x}{12}=\dfrac{2}{6}\)
<=> -5x . 6 = 12 . 2
<=> -30x = 24
<=> x = \(-\dfrac{4}{5}\)
(24 x 15 - 2\(x\)) - \(\dfrac{1}{4}\) = 400
24 x 15 - 2\(x\) = 400 + \(\dfrac{1}{4}\)
2\(x\) = 24 x 15 - \(\dfrac{1}{4}\) - 400
2\(x\) = - \(\dfrac{161}{4}\)
\(x\) = - \(\dfrac{161}{8}\)
b, 3200 : (8 + 3\(x\)) = 4
8 + 3\(x\) = 3200 : 4
8 + 3\(x\) = 800
3\(x\) = 800 - 8
3\(x\) = 792
\(x\) = 264
\(3200\div3x=4\)
\(3x=3200\div4\)
\(3x=800\)
\(x=800\div3\)
\(x=\dfrac{800}{3}\)