Question

[Diễm My]

Giúp t nhanh vs ạ lm đc bài nào thì lm nha t cảm ơn 

Answer 1

[HT.Phong (9A5)]

Bài 2:

\(a)2x^2y-\dfrac{1}{4}x^2y+5x^2y-4x^2y\\ =x^2y\cdot\left(2-\dfrac{1}{4}+5-4\right)\\ =x^2y\cdot\left(3-\dfrac{1}{4}\right)\\ =\dfrac{11}{4}x^2y\\ b)5y^3z^2-3y^3z^2+7y^3z^2-6y^3z^2\\ =y^3z^2\cdot\left(5-3+7-6\right)\\ =3y^3z^2\\ c)-4x^3y^4+6x^2y^3+\dfrac{1}{2}x^3y^4-\dfrac{3}{2}x^2y^3\\ =\left(\dfrac{1}{2}x^3y^4-4x^3y^4\right)+\left(6x^2y^3-\dfrac{3}{2}x^2y^3\right)\\ =x^3y^4\left(\dfrac{1}{2}-4\right)+x^2y^3\left(6-\dfrac{3}{2}\right)\\ =-\dfrac{7}{2}x^3y^4+\dfrac{9}{2}x^2y^3\)