Question

Rút gọn:

a) A = x (x + 3) + (x-1)(x+2)

b) B = (3x + 4)² - (x-4)(x+4) - 10x

Answer 1

`a, A = x(x+3) + (x-1)(x+2)`

`= x^2 + 3x + x^2 - x - 2`

`= x^2 + 2x - 2`

`b, (3x+4)^2 -(x+4)(x-4) - 10x`

`= 9x^2 + 24x + 16 - x^2 + 16 - 10x`

`= 8x^2 + 14x + 32`

Answer 2

`A = x (x + 3) + (x-1)(x+2)`

`A=x^2 +3x + x^2 -x-2`

`A=2x^2 +2x-2`

__________________________

`B = (3x + 4)^2 - (x-4)(x+4) - 10x`

`B=9x^2 +24x+16 - x^2 +16-10x`

`B=8x^2 +14x +32`