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\(\left(3x^{n+1}-2x^n\right).4x^2=12x^{n+3}-8x^{n+2}\)
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`@` `\text {Ans}`
`\downarrow`
`a)`
\(2x(4x²+x-3)\)
`= 2x*4x^2 + 2x*x + 2x*(-3)`
`= 8x^3 + 2x^2 - 6x`
`b)`
\([(-9x)+4x]: (-3x)-3x²\)
`= (-9x) \div (-3x) + 4x \div (-3x) - 3x^2`
`= 3 - 4/3 - 3x^2`
`= 5/3 - 3x^2`
![](https://rs.olm.vn/images/avt/0.png?1311)
Lời giải:
a.
$5x-[2x+1-(2x-3)-(4x+1)]=5x-(2x+1-2x+3-4x-1)$
$=5x-(-4x+3)=5x+4x-3=9x-3$
b.
$(-3x^2+2x-1)+(4x^2-2x+3)$
$=-3x^2+2x-1+4x^2-2x+3=x^2+2$
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a: =x^4-3x^5+4x^8
b: =2x^3+2x^2+4x
c: =4x^2+8x-5
d: =2x+3x^2+7x^4
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46:
\(A=\dfrac{2x^2\left(3x^2-2x+1\right)}{2x^2}-\left(3x^2-x-6x+2\right)\)
\(=3x^2-2x+1-3x^2+7x-2=5x-1\)
Khi x=-0,2 thì A=-1-1=-2
45:
a: \(=\dfrac{-5x^6}{3x^2}=-\dfrac{5}{3}x^4\)
c: \(=\dfrac{2x\left(2x^2-\dfrac{3}{2}x+1\right)}{2x}=2x^2-\dfrac{3}{2}x+1\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: \(=2x^3:\dfrac{-3}{2}x+4x:\dfrac{3}{2}x-5:\dfrac{3}{2}\)
=-4/3x^2+8/3-10/3
=-4/3x^2-2/3
d: \(\dfrac{3x^3-5x+2}{x-3}=\dfrac{3x^3-9x^2+9x^2-27x+22x-66+68}{x-3}\)
\(=3x^2+9x+22+\dfrac{68}{x-3}\)
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a: =3x^3-15x^2+21x
b: =-x^3+6x^2+5x-4x^2-24x-20
=-x^3+2x^2-19x-20
c: =9x^2+15x-3x-5-7x^2-14
=2x^2+12x-19
d: =10x^2-4x+2/3
Sửa đề : \(2x-\left|3x-9\right|=0\)
\(\Leftrightarrow\left|3x-9\right|=2x\)
\(\Leftrightarrow\orbr{\begin{cases}3x-9=2x\\-3x+9=2x\end{cases}\Leftrightarrow\orbr{\begin{cases}x=9\\-5x=-9\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=9\\x=\frac{9}{5}\end{cases}}}\)