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

10: =z(x+y)-2(x+y)=(x+y)(z-2)

11: =(2x+1)^2-(3y)^2

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

12: =(x-y)^2+4(x-y)

=(x-y)(x-y+4)

13; =(x-3y)^2-25z^2

=(x-3y-5z)(x-3y+5z)

a: =>(x+3)(5-2x)=0

=>x=-3 hoặc x=5/2

b: =>(x-3)(5x+20)=0

=>x=-4 hoặc x=3

c: =>(x-2)(5x+1)=0

=>x=2 hoặc x=-1/5

d: =>(x-1)(x+2)=0

=>x=-2 hoặc x=1

e: =>(2x+1)^2=0

=>2x+1=0

=>x=-1/2

f:=>(3x-5)(3x+3)=0

=>x=-1 hoặc x=5/3

a: =>x(x^2-1/4)=0

=>x(x-1/2)(x+1/2)=0

=>\(x\in\left\{0;\dfrac{1}{2};-\dfrac{1}{2}\right\}\)

b: =>(x-1)(5x-1)=0

=>x=1/5 hoặc x=1

c: =>(2x-1-x-3)(2x-1+x+3)=0

=>(x-4)(3x+2)=0

=>x=4 hoặc x=-2/3

e: =>(x+1)(x+4)=0

=>x=-1 hoặc x=-4

a:=>(x-3)(2x-5)=0

=>x=3 hoặc x=5/2

b: =>(x-2)(x+2)+(x-2)(2x-3)=0

=>(x-2)(x+2+2x-3)=0

=>(x-2)(3x-1)=0

=>x=1/3 hoặc x=1

c: =>(2x+5-x-2)(2x+5+x+2)=0

=>(x+3)(3x+7)=0

=>x=-7/3 hoặc x=-3

d: =>(x-2)(x-3)=0

=>x=2 hoặc x=3

e: =>(x+3)(x^2-3x+9+x-9)=0

=>(x+3)(x^2-2x)=0

=>\(x\in\left\{0;2;-2\right\}\)

f: =>(10x-5)^2=(2x-4)^2

=>(10x-5-2x+4)(10x-5+2x-4)=0

=>(8x-1)(12x-9)=0

=>x=3/4 hoặc x=1/8

18 D

23 C

24 B