\(ĐK:x\ge0\\ PT\Leftrightarrow\left(x-\dfrac{3}{4}\right)\left(x^2+\dfrac{3}{4}x+\dfrac{9}{16}\right)\left(\sqrt{x}-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\left(n\right)\\\sqrt{x}=3\left(n\right)\\x^2+2\cdot\dfrac{3}{8}x+\dfrac{9}{64}+\dfrac{27}{64}=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=9\\\left(x+\dfrac{3}{8}\right)^2+\dfrac{27}{64}=0\left(\text{vô nghiệm}\right)\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=9\end{matrix}\right.\)

\(a,=\left(x+3\right)^3=\left(7+3\right)^3=10^3=1000\\ b,=\left(4-x\right)^3=\left(4-24\right)^3=\left(-20\right)^3=-8000\\ c,=\left(x-1\right)^3=\left(11-1\right)^3=10^3=1000\)

\(x^3+\dfrac{3}{4}x+\dfrac{3}{2}x^2+\dfrac{1}{8}=\dfrac{1}{64}\)

\(\Leftrightarrow x+\dfrac{1}{2}=\dfrac{1}{4}\)

\(\Leftrightarrow x=-\dfrac{1}{4}\)

b,bang11000 

11000

a, 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3

a) `3x+5 =0`

`3x=-5`

`x=-5/3`

`b) -4x+8=0`

`-4x =-8`

`x=2`

`c) 3x -6=0`

`3x=6`

`x=2`

`d)x^2 +x =0`

`x(x+1) =0`

`=>[(x=0),(x=-1):}`

`e) x^2 -4 =0`

`x^2 =4`

`=> x = +-2`

`f) x^3 -27 =0`

`x^3 =27`

`=> x=3`

`g) 3x^2 +4 =0`

`3x^2 =-4`

`x^2 =-4/3(vô-lí)`

=> Đa thức ko có nghiệm

h) `x^3 -4x =0`

`x(x^2 -4) =0`

`=>[(x=0),(x^2=4 => x=+-2):}`

i) `2x^3 -32x =0`

`2x(x^2 -16)=0`

`=>[(2x=0),(x^2=16):}`

`=>[(x=0),(x=+-4):}`

a: \(\Leftrightarrow x\left(x-5\right)\left(x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=5\\x=-5\end{matrix}\right.\)

C:-16000

\(P=\left(x+4\right)\cdot\left(x^2-4x+16\right)-\left(64-x^3\right)\)

\(P=\left(x+4\right)\cdot\left(x^2-4x+4^2\right)-\left(64-x^3\right)\)

\(P=x^3+4^3-\left(64-x^3\right)\)

\(P=x^3+4^3-64+x^3=2x^3\)

Với : x = -20 

\(P=2\cdot\left(-20\right)^3=16000\)