1.

= (x^3 + 125 ) -(x^2 +5x)

=(x +5) (x^2 -5x +25) -x(x+5)

=(x+5)(x^2 -5x +25 -x)

=(x+5)(x^2 -6x +25)

2.

= (x^3 -27) + (2x^2 -6x)

=(x-3) (x^2 +3x +9) +2x (x-3)

=(x-3) (x^2 +3x +9 +2x)

=(x-3) (x^2 +5x +9)

3^3=27

=>x=3

b,5^2=25

=> x=5

a) \(x^2-xz-9y^2+3yz\)

\(=\left(x^2-9y^2\right)-\left(xz-3yz\right)\)

\(=\left(x-3y\right)\left(x+3y\right)-z\left(x-3y\right)\)

\(=\left(x-3y\right)\left(x+3y-z\right)\)

c) \(x^3+2x^2-6x-27\)

\(=\left(x^3-27\right)+\left(2x^2-6x\right)\)

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

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

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

b) \(x^3-x^2-5x+125\)

\(=\left(x^3+125\right)-\left(x^2+5x\right)\)

\(=\left(x+5\right)\left(x^2-5x+25\right)-x\left(5+x\right)\)

\(=\left(x+5\right)\left(x^2-5x+25-x\right)\)

\(=\left(x+5\right)\left(x^2-6x+25\right)\)

a ) \(x^3-x^2-5x+125\)

\(=\left(x^3+125\right)-\left(x^2+5x\right)\)

\(=\left(x+5\right)\left(x^2-5x+25\right)-x\left(x+5\right)\)

\(=\left(x+5\right)\left(x^2-5x+25-x\right)\)

\(=\left(x+5\right)\left(x^2-6x+25\right)\)

b ) \(x^3+2x^2-6x-27\)

\(=\left(x^3-27\right)+\left(2x^2-6x\right)\)

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

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

\(=\left(x-3\right)\left(x^2+5x+9\right)\)

a) x³ - x² - 5x + 125

=(x³-6x²+25x)+(5x²-30x+125)

=x(x²-6x+25)+5(x²-6x+25)

=(x+5)(x²-6x+25)

b) x³ + 2x² - 6x - 27

=x³+5x²+9-3x²-15x-27

=x(x²+5x+9)-3(x²+5x+9)

=(x-3)(x²+5x+9)

 a) x+x+x + 91 = -2

3x+91=-2

3x=-93

x=-31

b) -125 - (3x+1) = -2 . -27

-125-(3x+1)=54

-3x=54+126

-3x=180

x=-60

c) |5x +1| =14

\(\Leftrightarrow\orbr{\begin{cases}5x+1=14\\5x+1=-14\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{13}{5}\\x=-3\end{cases}}\)

P/s tham khảo nha

a) \(x+x+x+91=-2\)

\(3x=-93\)

\(x=-31\)

vậy \(x=-31\)

b) \(-125-\left(3x+1\right)=\left(-2\right).\left(-27\right)\)

\(-125-3x-1=54\)

\(-3x=54+1+125\)

\(-3x=180\)

\(x=-60\)

vậy \(x=-60\)

c) \(\left|5x+1\right|=14\)

\(\Rightarrow\orbr{\begin{cases}5x+1=14\\5x+1=-14\end{cases}}\Rightarrow\orbr{\begin{cases}5x=13\\5x=-15\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{13}{5}\\x=-3\end{cases}}\)

vậy \(\orbr{\begin{cases}x=\frac{13}{5}\\x=-3\end{cases}}\)

P/S: fan Khởi My ^_^ 

1/ a) \(2.3.12.12.3=2.3.2^2.3.2^2.3.3=2^5.3^4\)
    b) \(3.5.27.125=3.5.3^3.5^3=3^4.5^4=\left(3.5\right)^4\)
2/ a) \(\left(27^3\right)^4=27^{3.4}=27^{12}\)
Vậy \(\left(27^3\right)^4=27^{12}\)
b) \(5^{36}=\left(5^6\right)^6\)         và          \(11^{24}=\left(11^4\right)^6\)
Do đó \(5^6=15625\)      và        \(11^4=14641\)
Vì 15625>14641 nên\(\left(5^6\right)^6>\left(11^4\right)^6hay5^{36}>11^{24}.\)
3/ a) \(x^3=125=>x=5\)
b) \(\left(3x-14\right)^3=2^5.5^2+200\)
    \(\left(3x-14\right)^3=1000\)
    \(3x-14=10^3\)
    \(3x=10^3+14\)
    \(3x=1014\)
       \(x=\frac{1014}{3}=338\)
c) \(\left(2x-1\right)^4=81\)
    \(\left(2x-1\right)^4=3^4\)
    \(2x-1=3\)
     \(2x=3+1\)
        \(x=\frac{4}{2}=2\)
d) \(5x+3^4=2^2.7^2\)
    \(5x+3^4=\left(2.7\right)^2=14^2\)
    \(5x+81=196\)
    \(5x=196-81\)
    \(5x=115\)
       \(x=\frac{115}{5}=23\)
e) \(4^x=1024=>x=5\).

So sánh

A 5 mũ 36 và 11 mũ 24

B 7.2 mũ 13 và 2 mũ 16

tìm x

x mũ 2=121, 2 mũ x+3=1024, 5 mũ x+1=625

a) x³ - x² - 5x + 125

=(x³-6x²+25x)+(5x²-30x+125)

=x(x²-6x+25)+5(x²-6x+25)

=(x+5)(x²-6x+25)

b) x³ + 2x² - 6x - 27

=x³+5x²+9-3x²-15x-27

=x(x²+5x+9)-3(x²+5x+9)

=(x-3)(x²+5x+9)

c) 12x³ + 4x² - 27x - 9

=4x²(3x+1)-9(3x+1)

=(4x²-9)(3x+1)

=[(2x)²-3²](3x+1)

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

a) \(x^3-x^2-5x+125\)

\(=\left(x^3+125\right)-\left(x^2+5x\right)\)

\(=\left(x+5\right)\left(x^2-5x+25\right)-x\left(x+5\right)\)

\(=\left(x+5\right)\left(x^2-5x+25-x\right)=\left(x+5\right)\left(x^2-6x+25\right)\)

b) \(x^3+2x^2-6x-27\)

\(=\left(x^3-27\right)+\left(2x^2-6x\right)\)

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

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

\(=\left(x-3\right)\left(x^2+5x+9\right)\)

c) \(12x^3+4x^2-27x-9\)

\(=4x^2\left(3x+1\right)-9\left(3x+1\right)\)

\(=\left(3x-1\right)\left(4x^2-9\right)=\left(3x-1\right)\left(2x-3\right)\left(2x+3\right)\)

a) \(x^3-x^2-5x+125\)

\(=\left(x+5\right)\left(x^3-5x+25\right)-x\left(x+5\right)\)

\(=\left(x+5\right)\left(x^3-5x+25-x\right)\)

\(=\left(x+5\right)\left(x^3-6x+25\right)\)

a, \(x^2-xz-9y^2+3yz\)

\(=\left(x^2-9y^2\right)-\left(xz-3yz\right)\)

\(=\left(x-3y\right)\left(x+3y\right)-3z\left(x-3y\right)\)

\(=\left(x-3y\right)\left(x+3y-3z\right)\)

b, \(x^3-x^2-5x+125\)

\(=x^3+5x^2-6x^2-30x+25x+125\)

\(=x^2\left(x+5\right)-6x\left(x+5\right)+25\left(x+5\right)\)

\(=\left(x^2-6x+25\right)\left(x+5\right)\)

\(a,y-x^2y+2xy^2-y^3=y(1-x^2+2xy-y^2) =y[1-(x^2-2xy+y^2)]=y[1-(x-y)^2] =y(1-x+y)(1+x-y) =y(x+y-1)(x-y+1) \)