Question

Rút gọn hằng đẳng thức sau

a, 6x² -(2x - 3)(3x + 2) - 1.

b, (x - 3)(x + 7) - (x + 5)(x - 1).

 

 

Answer 1

`a, 6x^2 - 6x^2 + 9x - 4x + 6 - 1`

`= 5x + 5`

`b, x^2 + 4x - 21 - x^2 - 4x + 5`

`= -16`.

Answer 2

\(a,=6x^2-\left(6x^2-9x+4x-6\right)-1\\ =6x^2-6x^2+5x+6-1\\ =5x+5\\ =5\left(x+1\right)\\ b,=x^2-3x+7x-21-\left(x^2+5x-x-5\right)\\ =x^2+4x-21-x^2-4x+5\\ =-16\)

Answer 3

a) 6x² - (2x - 3)(3x + 2) - 1

= 6x² - 6x² - 4x + 9x + 6 - 1

= 5x + 5

b)(x - 3)(x + 7) - (x + 5)(x - 1)

= x² + 7x - 3x - 21 - x² + x - 5x + 5

= -16