a) 2(3x - 1) = 10

3x - 1 = 10 : 2

3x - 1 = 5

3x = 5 + 1

3x = 6

x = 6 : 3

x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

9x² + 24x + 16 - 9x² + 1 = 49

24x + 17 = 49

24x = 49 - 17

24x = 32

x = 32 : 24

a) (5x³y² - 3x²y + xy) : xy

= 5x³y² : xy + (-3x²y : xy) + xy : xy

= 5x²y - 3x + 1

b) A + 2M = P

A = P - 2M

= 3x³ - 2x²y - xy + 3 - 2.(x³ - x²y + 2xy + 3)

= 3x³ - 2x²y - xy + 3 - 2x³ + 2x²y - 4xy - 6

= (3x³ - 2x³) + (-2x²y + 2x²y) + (-xy - 4xy) + (3 - 6)

= x³ - 5xy - 3

Vậy A = x³ - 5xy - 3

a) \(\left(\right. x - 2 y \left.\right) \left(\right. 3 x y + 6 x^{2} + x \left.\right)\)

a) \(\left(\right. x - 2 y \left.\right) \left(\right. 3 x y + 6 x^{2} + x \left.\right)\)

\(= x \left(\right. 3 x y + 6 x^{2} + x \left.\right) - 2 y \left(\right. 3 x y + 6 x^{2} + x \left.\right)\)

\(= 3 x^{2} y + 6 x^{3} + x^{2} - 6 x y^{2} - 12 x^{2} y - 2 x y\)

\(= 6 x^{3} + x^{2} - 9 x^{2} y - 6 x y^{2} - 2 x y\)

b) \(\left(\right. 18 x^{4} y^{3} - 24 x^{3} y^{4} + 12 x^{3} y^{3} \left.\right) : \left(\right. - 6 x^{2} y^{3} \left.\right)\)

\(= 18 x^{4} y^{3} : \left(\right. - 6 x^{2} y^{3} \left.\right) - 24 x^{3} y^{4} : \left(\right. - 6 x^{2} y^{3} \left.\right) + 12 x^{3} y^{3} : \left(\right. - 6 x^{2} y^{3} \left.\right)\)

\(= - 3 x^{2} + 4 x y - 2 x\)