Question

Làm tính nhân:

a) (3x²y - 11x² - 5y)(8xy - 5x + 6)

b) (-4x²y - 5x² + 3y³)(2x² - xy + 3y²)

Answer 1

a) \(\left(3x^2y-11x^2-5y\right)\left(8xy-5x+6\right)\)

\(=3x^2y\left(8xy-5x+6\right)-11x^2\left(8xy-5x+6\right)-5y\left(8xy-5x+6\right)\)

\(=24x^3y^2-15x^3y+18x^2y-88x^3y+55x^3-66x^2-40xy^2+25xy-30y\)

\(=24x^3y^2-103x^3y+18x^2y+55x^3-66x^2-40xy^2+25xy-30y\)

b) \(\left(-4x^2y-5x^2+3y^3\right)\left(2x^2-xy+3y^2\right)\)

\(=-4x^2y\left(2x^2-xy+3y^2\right)-5x^2\left(2x^2-xy+3y^2\right)+3y^3\left(2x^2-xy+3y^2\right)\)

\(=-8x^4y+4x^3y^2-12x^2y^3-10x^4+5x^3y-15x^2y^2+6x^2y^3-3xy^4+9y^5\)

\(=-8x^4y+4x^3y^2-6x^2y^3-10x^4+5x^3y-15x^2y^2-3xy^4+9y^5\)

P/s: Ko chắc ạ!