(x-1)^2=9
(X-3)^3+15=7
Giải hộ mình với mn :(((((
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`1 / 3 + 2 / 3 : x = -7`
`2 / 3 : x = -7 - 1 / 3`
`2 / 3 : x = -22 / 3`
`x = 2 / 3 : -22 / 3`
`x = -1 / 11`
\(\dfrac{-28}{4}< x\le\dfrac{-21}{7}\)
\(\Rightarrow-7< x\le-3\)
Nếu x ∈ Z thì:
\(x\in\left\{-6;-5;-4;-3\right\}\)
\(\dfrac{-28}{4}< x\le\dfrac{-21}{7}\)
\(\Leftrightarrow-4< x\le-3\)
Nếu x nguyên thì x = -3
a: \(\Leftrightarrow\left(2-x\right)\left(x-3\right)+\left(x-1\right)\left(x+3\right)=-4x\)
\(\Leftrightarrow2x-6-x^2+3x+x^2+3x-x-3=-4x\)
=>7x-9=-4x
=>11x=9
hay x=9/11
b: \(\Leftrightarrow\left(5-x\right)\left(x-4\right)+\left(x+2\right)\left(x+4\right)=-3x\)
\(\Leftrightarrow5x-20-x^2+4x+x^2+6x+8=-3x\)
=>15x-12=-3x
=>18x=12
hay x=2/3
Câu 1:
0,9 x 218 x 2 + 0,18 x 4290 + 0,6 x 353 x 3
= 9/10 x 436 + 9/50 x 4290 + 6/10 x 1059
= 9 x 43,6 + 9 x 85,8 + 6 x 105,9
= 3 x 130,8 + 3 x 257,4 + 3 x 211,8
= 3 x ( 130,8 + 257,4 + 211,8 )
= 3 x 600
= 1800
Câu 2:
3/4 x X + 1/2 x X - 15 = 35
X x ( 3/4 + 1/2 ) - 15 = 35
X x ( 3/4 + 1/2 ) = 50
X x 5/4 = 50
X = 40
VẬy X = 40
a)=1/2 . 8/15 - 3/4.47/9
=4/15 - 47/12
=-73/20
b)=2-1/3 . -21/20
=2+7/20
=47/20
\(\dfrac{4}{3}\cdot\dfrac{9}{8}\cdot\dfrac{16}{15}\cdot...\cdot\dfrac{400}{399}\)
\(=\dfrac{2\cdot2}{1\cdot3}\cdot\dfrac{3\cdot3}{2\cdot4}\cdot\dfrac{4\cdot4}{3\cdot5}\cdot...\cdot\dfrac{20\cdot20}{19\cdot21}\)
\(=\dfrac{2\cdot2\cdot3\cdot3\cdot4\cdot4\cdot...\cdot20\cdot20}{1\cdot3\cdot2\cdot4\cdot3\cdot5\cdot...\cdot19\cdot21}\)
\(=\dfrac{2\cdot3\cdot4\cdot...\cdot20}{1\cdot2\cdot3\cdot...\cdot19}\cdot\dfrac{2\cdot3\cdot4\cdot...\cdot20}{3\cdot4\cdot5\cdot...\cdot21}\)
\(=20\cdot\dfrac{2}{21}\)
\(=\dfrac{40}{21}\)
\(3\left(x-2\right)^2+9\left(x-1\right)=3\left(x^2+x-3\right)\\ \Leftrightarrow3\left(x^2-4x+4\right)+9x-9=3x^2+3x-9\\ \Leftrightarrow3x^2-12x+12+9x-9-3x^2-3x+9=0\\ \Leftrightarrow-6x+12=0\\ \Leftrightarrow x=2\)
\(3\left(x-2\right)^2+9\left(x-1\right)=3\left(x^2+x-3\right)\)
\(\Leftrightarrow3\left(x^2-4x+4\right)+9x-9=3x^2+3x-9\)
\(\Leftrightarrow3x^2-12x+12+9x-9-3x^2-2x+9=0\)
\(\Leftrightarrow-6x-6=0\)
\(\Leftrightarrow-6\left(x+1\right)=0\)
\(\Leftrightarrow x+1=0\)
\(\Leftrightarrow x=-1\)
Vậy phương trình có nghiệm là \(-1\)
(x-1)^2=9
=> (x-1)^2 = 3^2
=> x-1= 3
=> x = 3 + 1
=> x =4
\(\left(x-1\right)^2=9\)
\(\Leftrightarrow\left(x-1\right)^2=3^2\)
\(\Leftrightarrow\orbr{\begin{cases}x-1=3\\x-1=-3\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3+1\\x=-1+3\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=4\\x=2\end{cases}}}\)
Vậy \(x=4\)hoặc \(x=2\)
\(\left(x-3\right)^3+15=7\)
\(\Leftrightarrow\left(x-3\right)^3=7-15\)
\(\Leftrightarrow\left(x-3\right)^3=-8\)
\(\Leftrightarrow\left(x-3\right)^3=\left(-2\right)^3\)
\(\Leftrightarrow x-3=-2\)
\(\Leftrightarrow x=-2+3\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)