a,\(\left(3x-2\right)\left(x+6\right)\left(x^2+5\right)=0\)

Ta có: \(x^2+5\ge0\) (vô lí)

\(\Leftrightarrow\orbr{\begin{cases}3x-2=0\\x+6=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{2}{3}\\x=-6\end{cases}}\)

Vậy ....

c, \(4x^2\left(x-1\right)-x+1=0\)

\(\Leftrightarrow4x^3-4x^2-x+1=0\)

\(\Leftrightarrow4x^2\left(x-1\right)-\left(x-1\right)=0\)

\(\Leftrightarrow\left(4x^2-1\right)\left(x-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}4x^2-1=0\\x-1=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}4x^2=1\\x=1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x^2=\frac{1}{4}\\x=1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\pm\frac{1}{2}\\x=1\end{cases}}\)

Vậy ....

\(\frac{x+2}{x+3}-\frac{x+1}{x-1}=\frac{4}{\left(x-1\right)\left(x+3\right)}\)

ĐKXĐ: \(x\ne1,x\ne-3\)

PT đã cho \(\Leftrightarrow\frac{\left(x+2\right).\left(x-1\right)-\left(x+1\right).\left(x+3\right)}{\left(x+3\right).\left(x-1\right)}=\frac{4}{\left(x-1\right)\left(x+3\right)}\)

\(\Leftrightarrow\frac{\left(x+2\right).\left(x-1\right)-\left(x+1\right).\left(x+3\right)}{\left(x+3\right).\left(x-1\right)}=\frac{4}{\left(x-1\right)\left(x+3\right)}\)

\(\Rightarrow x^2+x-2-x^2-4x-3=4\Leftrightarrow3x=-1\Leftrightarrow x=\frac{-1}{3}\)

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_ Hok tốt _

a) \(6x^4+7x^3-37x^2-8x+12\)

\(=\left(6a^4+6a^3-36a^2\right)+\left(a^3+a^2-6a\right)+\left(-2a^2-2a+12\right)\)

\(=6a^2\left(a^2+a-6\right)+a\left(a^2+a-6\right)-2\left(a^2+a-6\right)\)

\(=\left(a^2+a-6\right)\left(6a^2+a-2\right)\)

Em làm tiếp nhé

b) Hướng dẫn:

=\(\left(x^2+4x+8\right)^2-\left(2x\right)^2+\left(2x\right)^2+3x^3+14x^2+24x\)

\(=\left(x^2+2x+8\right)\left(x^2+6x+8\right)+\left(3x^3+18x^2+24x\right)\)

\(=\left(x^2+6x+8\right)\left(x^2+2x+8+3x\right)\)

Em làm nhé!

Ta có :

| 2 + 3x | - | 4x - 3 | = 0

\(\Rightarrow\)| 2 + 3x | = | 4x - 3 |

\(\Rightarrow\)2 + 3x = \(\pm\)( 4x - 3 )

Ta xét 2 trường hợp :

Th 1 :

2 + 3x = 4x - 3

3x - 4x = - 3 - 2

- x = - 5

\(\Rightarrow\)x = 5

Th 2 :

2 + 3x = - ( 4x - 3 )

2 + 3x = - 4x + 3

3x + 4x = 3 - 2

7x = 1

\(\Rightarrow\)x = \(\frac{1}{7}\)

Vậy x \(\in\){ 5 ; \(\frac{1}{7}\)}

\(\left(x+3\right)^3-x\left(3x-1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)=28\)

\(\Leftrightarrow x^3+9x^2+27x+27-x\left(9x^2-6x+1\right)+8x^3-4x^2+2x+4x^2-2x+1=28\)

\(\Leftrightarrow x^3+9x^2+27x+27-9x^3+6x^2-x+8x^3-4x^2+2x+4x^2-2x+1-28=0\)

\(\Leftrightarrow15x^2+26x=0\)

\(\Leftrightarrow15x\left(x+\frac{26}{15}\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}15x=0\\x+\frac{26}{15}=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=-\frac{26}{15}\end{cases}}}\)