a, -2/3 + 2x = 4/3 b, 5/8 - 5 : x = -3/8 c, 2/3 - x = -1/2 d, 5/7 - 4x = -51/7
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\(a)5\left(3-2x\right)+5\left(x-4\right)=6-4x\)
\(\Leftrightarrow5\left(3-2x+x-4\right)=6-4x\)
\(\Leftrightarrow5\left(-x-1\right)=6-4x\)
\(\Leftrightarrow-5x-5=6-4x\)
\(\Leftrightarrow-x=11\Leftrightarrow x=-11\)
Vậy \(x=-11\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,3\left(2x-3\right)+2\left(2-x\right)=-3\\ \Leftrightarrow6x-9+4-2x=-3\\ \Leftrightarrow4x=2\\ \Leftrightarrow x=\dfrac{1}{2}\\ b,x\left(5-2x\right)+2x\left(x-1\right)=13\\ \Leftrightarrow5x-2x^2+2x^2-2x=13\\ \Leftrightarrow3x=13\\ \Leftrightarrow x=\dfrac{13}{3}\\ c,5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\\ \Leftrightarrow5x^2-5x-5x^2-3x+14=6\\ \Leftrightarrow-8x=-8\\ \Leftrightarrow x=1\\ d,3x\left(2x+3\right)-\left(2x+5\right)\left(3x-2\right)=8\\ \Leftrightarrow6x^2+9x-6x^2-11x+10=8\\ \Leftrightarrow-2x=-2\\ \Leftrightarrow x=1\)
\(e,2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\\ \Leftrightarrow10x-16-12x+15=12x-16+11\\ \Leftrightarrow-14x=-4\\ \Leftrightarrow x=\dfrac{2}{7}\\ f,2x\left(6x-2x^2\right)+3x^2\left(x-4\right)=8\\ \Leftrightarrow12x^2-4x^3+3x^3-12x^2=8\\ \Leftrightarrow-x^3-8=0\\ \Leftrightarrow-\left(x^3+8\right)=0\\ \Leftrightarrow-\left(x+2\right)\left(x^2-2x+4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-2\\x\in\varnothing\left(x^2-2x+4=\left(x-1\right)^2+3>0\right)\end{matrix}\right.\)
Bài 4:
a: Ta có: \(3\left(2x-3\right)-2\left(x-2\right)=-3\)
\(\Leftrightarrow6x-9-2x+4=-3\)
\(\Leftrightarrow4x=2\)
hay \(x=\dfrac{1}{2}\)
b: Ta có: \(x\left(5-2x\right)+2x\left(x-1\right)=13\)
\(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
\(\Leftrightarrow3x=13\)
hay \(x=\dfrac{13}{3}\)
c: Ta có: \(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
\(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
\(\Leftrightarrow-8x=-8\)
hay x=1
![](https://rs.olm.vn/images/avt/0.png?1311)
\(1,\\ a,=7x^3-49x^2+21x\\ b,=x^2-x-42\\ c,=x^2-16x+64\\ d,=9x^2+12x+4\\ e,=x^2-16-25+10x-x^2=10x-41\\ 2,\\ a,\Rightarrow2\left(x-7\right)=19\\ \Rightarrow x-7=\dfrac{19}{2}\Rightarrow x=\dfrac{33}{2}\\ b,\Rightarrow4x^2-20x+25-4x^2+3x-2x=50\\ \Rightarrow-19x=25\Rightarrow x=-\dfrac{25}{19}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
nhiều quá :((
\(a,2\left(x-5\right)-3\left(x+7\right)=14\)
\(2x-10-3x-21=14\)
\(-x-31=14\)
\(-x=45\)
\(x=45\)
\(b,5\left(x-6\right)-2\left(x+3\right)=12\)
\(5x-30-2x-6=12\)
\(3x-36==12\)
\(3x=48\)
\(x=16\)
\(c,3\left(x-4\right)-\left(8-x\right)=12\)
\(3x-12-8+x=0\)
\(4x-20=0\)
\(4x=20\)
\(x=5\)
Cố nốt nha bn !
cảm ơn, bn nha:)))
mà hình như bạn TOP 3 trả lời câu hỏi pải ko nhỉ???
Lời giải:
a.
$\frac{-2}{3}+2x=\frac{4}{3}$
$2x=\frac{4}{3}-\frac{-2}{3}=2$
$x=2:2=1$
b.
$\frac{5}{8}-5:x=\frac{-3}{8}$
$5:x=\frac{5}{8}-\frac{-3}{8}=1$
$x=5:1=5$
c.
$\frac{2}{3}-x=\frac{-1}{2}$
$x=\frac{2}{3}-\frac{-1}{2}=\frac{7}{6}$
d.
$\frac{5}{7}-4x=\frac{-51}{7}$
$4x=\frac{5}{7}-\frac{-51}{7}=8$
$x=8:4=2$
`@` `\text {Ans}`
`\downarrow`
`a,`
`-2/3 + 2x = 4/3`
`=> 2x = 4/3 - (-2/3)`
`=> 2x = 2`
`=> x=2 \div 2`
`=> x=1`
Vậy, `x=1`
`b,`
`5/8 - 5 : x = -3/8`
`=> 5 \div x = 5/8 - (-3/8)`
`=> 5 \div x = 1`
`=> x= 5 \div 1`
`=> x=5`
Vậy, `x=5`
`c,`
`2/3 - x = -1/2`
`=> x=2/3 - (-1/2)`
`=> x=7/6`
Vậy, `x=7/6`
`d,`
`5/7 - 4x = -51/7`
`=> 4x = 5/7 - (-51/7)`
`=> 4x=8`
`=> x=8 \div 4`
`=> x=2`
Vậy, `x=2.`
`@` `\text {Kaizuu lv u}`