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\(231-2.\left(x-6\right)=1339:13\)
\(231-2x+12=103\)
\(2x+12=128\)
\(2x=116\)
\(x=58\)
Vậy \(x=58\)
<=> \(7x=5^2+3\)
<=> \(7x=28\)
<=> \(x=4\)
Vay x=4
chuc ban hoc tot !!!
6x + x = 511 : 59 + 31
7x = 52 + 3
7x = 25 + 3
7x = 28
x = 28 : 7
x = 4.
~ Chúc em học tốt nha ~ :3
\(1,4:4,9=x:\left(-28\right)\)
\(\Rightarrow\frac{1,4}{4,9}=\frac{x}{-28}\)
\(\Leftrightarrow1,4.\left(-28\right)=4,9x\)
\(\Leftrightarrow-39,2=4,9x\)
\(\Leftrightarrow x=-8\)
#H
Ta có: 1,4/4,9= x/-28
=> 1,4. (-28)= 4,9.x
=> -39,2= 4,9.x
=> x= -39,2: 4,9
=> x= -8
S = 1x2 + 2x3 + 3x4 + ... + 38x39 + 39x40
3S = 1x2x3 + 2x3x3 + 3x4x3 + ... + 38x39x3 + 39x40x3
3S = 1x2x3 + 2x3x(4-1) + 3x4x(5-2) + ... + 38x39x(40-37) + 39x40x(41-38)
3S = 1x2x3 + 2x3x4-1x2x3 + 3x4x5-2x3x4 + ... + 38x39x40-37x38x39 + 39x40x41-38x39x40
S = 39x40x41 : 3
S = 21320
\(3S=1.2.3+2.3.3+...+39.40.3\)
\(3S=1.2.\left(3-0\right)+2.3.\left(4-1\right)+...+39.40.\left(41-38\right)\)
\(3S=0.1.2-1.2.3+1.2.3-2.3.4+...+38.39.40-39.40.41\)
\(3S=30.40.41\)
\(S=10.40.41\)
`@` `\text {Ans}`
`\downarrow`
\(\left(\dfrac{x}{3}+\dfrac{1}{2}\right)\left(75\%-1\dfrac{1}{2}x\right)=0\)
`=>`\(\left[{}\begin{matrix}\dfrac{x}{3}+\dfrac{1}{2}=0\\\dfrac{75}{100}-\dfrac{3}{2}x=0\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}\dfrac{x}{3}=-\dfrac{1}{2}\\\dfrac{3}{2}x=\dfrac{75}{100}\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}2x=-1\cdot3\\x=\dfrac{75}{100}\div\dfrac{3}{2}\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}2x=-3\\x=\dfrac{1}{2}\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=\dfrac{1}{2}\end{matrix}\right.\)
Vậy, `x={-3/2; 1/2}.`
`Answer:`
\(12x-144=0\)
\(\Leftrightarrow12x=144\)
\(\Leftrightarrow x=144:12\)
\(\Leftrightarrow x=12\)
\(5x-32:18=13\)
\(\Leftrightarrow5x-\frac{16}{9}=13\)
\(\Leftrightarrow5x=13+\frac{16}{9}\)
\(\Leftrightarrow5x=\frac{133}{9}\)
\(\Leftrightarrow x=\frac{133}{9}:5\)
\(\Leftrightarrow x=\frac{133}{45}\)
\(3x+6=15\)
\(\Leftrightarrow3x=9\)
\(\Leftrightarrow x=3\)
a có:
Vậy
Chúc bạn học tốt!
5x+x=75+3
5x+x=78
5x+1x=78
(5+1)x=78
6x=78
x=78:6
x=13