a) (2x + 1)^2 

= 4x^2 +4x + 1

b) (a-b/2) ^3

= a^3 - 3/2 a^2b + 3/4 ab^2 - 1/8 b^3

a) 3x (x-1 ) -1 + x =0 

 3x( x - 1) + ( x -1 ) =0

(3x+1 ) (x-1)=0

3x+1 =0 => 3x = -1 => x= -1/3

x-1 =0 => x=1

b) x^2 -9x =0

x (x-9 )=0

X=0 

x-9 =0 => x=9

a) x^2 + 25 - 10x

= x^2 -10x +25 

= ( x- 5)^2

b) -8y^3+ x^3

= x^3 - 8y^3 

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