a, 2x(x+3) +(3+x) = (x + 3) (2x + 1)
b. 4xn+2 + 8xn ( n thuộc N*)
= 4xn (x2 + 2)
c. ( x - 1)2 + y(x - 1) = (x - 1) (x - 1 + y)
d. 4x(x - 2) - (2 - x)2 = 4x(x - 2) - (x - 2)2 = (x - 2) (4x - x + 2) = (x - 2) (3x + 2)
e. (x - 2)2 - (2 - x)3 = (2 - x)2 - (2 - x)3 = (2 - x)2 (1 - 2 + x) = (2 - x)2 (x - 1)