Question

分解因式(a一b)(a一4b)十ab的结果为

Answer 1

(a-b)(a-4b)+ab
=a²-4ab-ab+4b²+ab
=a²-4ab+4b²
=(a-2b)²

Answer 2

=a²-5ab+4b²+ab
=a²-4ab+4b²
=(a-2b)²

Answer 3

=a^2-4ab-ab+4b^2+ab=a^2-4ab+4b^2= (a-2b)^2