giúp mik bài 3 vs maayys bạn eiiiii

0 thoughts on “giúp mik bài 3 vs maayys bạn eiiiii”

1. a.

   `A = a(b + 3) – b(3 + b)`

   `=a(b + 3) – b(b + 3)`

   `=(b + 3)(a – b)` (1)

   Thay a = 2003, b = 1997 vào (1), ta có:

   `=(1997 + 3)(2003 – 1997)`

   `=2000 * 6 = 12000`

   b.

   `B = b^2 – 8b – c(8 – b)`

   `=(b^2 – 8b) – c(8 – b)`

   `=b(b – 8) – c(8 – b)`

   `=-b(8 – b) – c(8 – b)`

   `=-(8 – b)(b + c)` (2)

   Thay b = 108, c = -8 vào (2), ta có:

   `=-(8-108)[108 + (-8)]`

   `=10000`

   c.

   `C = xy(x + y) – 2x – 2y`

   `=xy(x + y) – (2x + 2y)`

   `=xy(x + y) – 2(x + y)`

   `=(x + y)(xy – 2)` (3)

   Thay xy = 8, x + y = 7 vào (3), ta có:

   `=7 * (8 – 2)`

   `=42`

   d.

   `D = x^5(x + 2y) – x^3y(x + 2y) + x^2y^2(x + 2y)`

   `=(x + 2y)(x^5 – x^3y + x^2y^2)` (4)

   Thay x = 10, y = -5 vào (4), ta có:

   `=[10 + 2 * (-5)][10^5 – 10^3*(-5) + 10^2*(-5)^2]`

   `=0`

   Reply