Bài làm:
1)3x2 + 5y - 3xy - 5x = (3x2 - 3xy) + (5y - 5x)
= 3x(x - y) + 5(y - x)
= 3x(x - y) - 5(x - y)
(3x - 5)(x - y)
2)3y2 - 3z2 + 3x2 + 6xy = (3x2 + 6xy + 3y2) - 3z2
= (\(\sqrt{3x}\) + \(\sqrt{3y}\))2 - (\(\sqrt{3z}\))2
= (\(\sqrt{3x}\) + \(\sqrt{3y}\) - \(\sqrt{3z}\)).(\(\sqrt{3x}\) + \(\sqrt{3y}\) + \(\sqrt{3z}\))
4)x2 - 25 - 2xy + y2 = (x2 - 2xy + y2) - 25
= (x - y)2 - 52
= (x - y - 5).(x - y + 5)
5)x5 - 3x4 + 3x3 - x2 = x2.(x3 - 3x2 - 3x - 1)
Còn câu 3) Vàng sẽ nghĩ sau :v
3. \(16x^3+54x^3\)
\(=2x^3\left(8+27\right)\)
