a) A = (5x³y² - 3x²y + xy) : xy

= (5x³y² : xy) + (-3x²y : xy) + ( xy : xy)

= 5x²y - 3x + 1}

b) Ta có A + 2M = P

Suy ra A = P - 2M

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

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

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

A = x³ - 5xy - 3

Vậy với A + 2M = P, ta có A = x³ - 5xy - 3

:))

a) 2(3x - 1) = 10

3x - 1= 10 : 2

3x - 1= 5

3x = 5 + 1

3x = 6

x = 6:3 =2

Vậy x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

(3x)² + 2•3x•4 + 4²)[(3x)² - 1²]= 49

(9x² + 24x + 16) - (9x² - 1) = 49

9x² + 24x + 16 - 9x² + 1 = 49

(9x² - 9x²) + 24x + (16 + 1) = 49

24x + 17 = 49

24x = 49 - 17

24x = 32

x = 32/24