a)

\(x^3-7x-6=x^3+1-7x-7\)

= \(\left(x+1\right)\left(x^2-x+1\right)-7\left(x+1\right)\)

= \(\left(x+1\right)\left(x^2-x+1-7\right)\)

= \(\left(x+1\right)\left(x^2-x-6\right)\)

b)

\(x^3-5x^2-14x=x^3+2x^2-7x^2-14x\)

= \(x^2\left(x+2\right)-7x\left(x+2\right)\)

= \(\left(x^2-7x\right)\left(x+2\right)\)

= \(x\left(x-7\right)\left(x+2\right)\)

a,x^3 -x-6x-6 = x(x^2 -1)-6(x+1)= x(x-1)(x+1)-6(x+1)=(x+1)(X^2-x-6)=(x+1)(x^2+2x-3x-6)=(x+1)(x(x+2)-3(x+2))=(x+1)(x+2)(x-3)

b,x(x^2-5x-14)=x(x^2+2x-7x-14)=x(x(x+2)-7(x+2))=x(x+2)(x-7)

1) \(x^2-6x+3\)

\(=x^2-6x+9-6\)

\(=\left(x-3\right)^2-6\)

\(=\left(x-3+\sqrt{6}\right)\left(x-3-\sqrt{6}\right)\)

2) \(2m^2+10m+8\)

\(=2m^2+2m+8m+8\)

\(=2m\left(m+1\right)+8\left(m+1\right)\)

\(=\left(2m+8\right)\left(m+1\right)\)

\(=2\left(m+4\right)\left(m+1\right)\)

3) \(9x^2+6x-8\)

\(=\left(9x^2+6x+1\right)-9\)

\(=\left(3x+1\right)^2-9\)

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

4) \(x^3-5x^2-14x\)

\(=x\left(x^2-5x-14\right)\)

\(=x\left(x^2-2x+7x-14\right)\)

\(=x\left[x\left(x-2\right)+7\left(x-2\right)\right]\)

\(=x\left(x+7\right)\left(x-2\right)\)

1) x^2-6x+3

= (x^2-6x+9)-6

=(x-3)^2-6

=(x-3-căn 6)(x-3+căn 6)

2) =2(m^2+5m+4)

=2(m+1)(m+4)

3) =9x^2+6x+1-9

=(3x+1)^-9

=(3x-2)(3x+4)

4, x^3-5x^2-14x

=x(x-7)(x+2)

5, a^4+4a^2-5

=a^4+4a^2+4-9

=(a^2+2)^-9

=(a^2-1)(a^2+5)

6, x^3-7x-6

=(x-3)(x+1)(x+2).

b. 2x³-3x²+3x-1=2x³-x²-2x²+x+2x-1

= x²(2x-1)-x(2x-1)+(2x-1)

=(2x-1)(x²-x-1)

c. 3x³-14x²+4x+3= 3x³+x²-15x²-5x+9x+3

=x²(3x+1)-5x(3x-1)+3(3x+1)

=(3x+1)(x²-5x+3)

b) \(6x^2-13x+5=6x^2-3x-10x+5\)

\(=3x\left(2x-1\right)-5\left(2x-1\right)\)

\(=\left(2x-1\right).\left(3x-5\right)\)

d) \(3x^2-11x+6=3x^2-9x-2x+6\)

\(=3x\left(x-3\right)-2\left(x-3\right)\)

\(=\left(x-3\right)\left(3x-2\right)\)

e) \(-7x^2+11x+6=-7x^2+14x-3x+6\)

\(=-7x\left(x-2\right)-2\left(x-2\right)\)

\(=\left(x-2\right)\left(-7x-2\right)\)

`1/14x+5/7=-3/2`

`=>1/14x=-3/2-5/7`

`=>1/14x=-21/14-10/14`

`=>1/14x=-31/14`

`=>x=-31/14 : 1/14`

`=>x=-31/14 . 14`

`=>x=-31`

Vậy `x=-31`

`#QiN`

\(\dfrac{1}{14}x+\dfrac{5}{7}=-\dfrac{3}{2}\) (đề ntn phải ko ạ?)

`=> 1/14x=-3/2-5/7`

`=>1/14x=-31/14`

`=>x=-31/14:1/14`

`=>x=-31`

\(5x^2+14x-432\)
\(=\left(5x^2+54x\right)-\left(40x+432\right)\)
\(=x\left(5x+54\right)-8\left(5x+54\right)\)
\(=\left(5x+54\right)\left(x-8\right)\)
#kễnh

7^2.x-14x=7^2.10-70

49x-14x=49.10-70

(49-14)x=490-70

35x=420

x=420/35

x=12

\(a,ĐK:x\ge-7\\ PT\Leftrightarrow\sqrt{\left(\sqrt{x+7}+1\right)^2}+\sqrt{x+7-\sqrt{x+7}-6}=4\)

Đạt \(\sqrt{x+7}=a\ge0\)

\(PT\Leftrightarrow\sqrt{\left(a+1\right)^2}+\sqrt{a^2-a-6}=4\\ \Leftrightarrow a+1+\sqrt{a^2-a-6}=4\\ \Leftrightarrow\sqrt{a^2-a-6}=3-a\\ \Leftrightarrow a^2-a-6=a^2-6a+9\\ \Leftrightarrow5a=15\Leftrightarrow a=3\\ \Leftrightarrow\sqrt{x+7}=3\\ \Leftrightarrow x+7=9\\ \Leftrightarrow x=2\left(tm\right)\)

14x - 2 . 7² = 42

14x=140

x=10

ghi rõ cách làm cho mình nha!!!