Tham khảo:

bài 5
a) 2^n . 4 = 128
=> 2^n=32
=> 2^n=2^5
=> n=5
b) (2n+1)^3=125
=> (2n+1)^3=5^3
=> 2n+1=5
=> 2n=4
=> n=2

bài 4
a) 3^3 . 27 : 81
=27.27:81
=729:81=9
b)100.1000.10000-10^9
=10^9-10^9=0

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

mờ quá bạn ơi:(

Bài 16
a)  \(=x^2-2x-3x+6\)

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

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

c) \(=x^2-x-2x+2\)

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

d) \(=x^2-3x-6x+18\)

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

e) \(=x^2-2x-4x+8=x\left(x-2\right)-4\left(x-2\right)=\left(x-4\right)\left(x-2\right)\)

g) \(=x^2+x+5x+5=x\left(x+1\right)+5\left(x+1\right)=\left(x+5\right)\left(x+1\right)\)

h) \(=x^2-3x-4x+12=x\left(x-3\right)-4\left(x-3\right)=\left(x-4\right)\left(x-3\right)\)

i) \(=x^2+2x+5x+10=x\left(x+2\right)+5\left(x+2\right)=\left(x+5\right)\left(x+2\right)\)