@Sun
Mk gửi bài nha !!!
Bài 4:
a, 2x + 4y = 2(x + 2y)
b, 1/4x² + xy + x = x(1/4x + y) + x
= x(1/4x + y + 1)
c, x³y + 2xy + xy² = xy(x² + 2 +y)
d, x(y+1) - 2y(y + 1) = (y + 1)(x - 2y)
e, x²(x + y) - y(x + y) = (x + y)(x² - y)
f, x(y - x) + 2y(y - x) = (y - x)(x + 2y)