Question

[Đỗ Thị Hương Xuân]

Rút Gọn

a) (x+2)(x-2)-(x-3)(x+1)
b) (2x+1)^2+(3x-1)^2+2.(2x+1)(2x-1)

Answer 1

[Kiệt Nguyễn]

a) \(\left(x+2\right)\left(x-2\right)-\left(x-3\right)\left(x+1\right)\)

\(=\left(x^2-4\right)-\left(x^2-2x-3\right)\)

\(=x^2-4-x^2+2x+3\)

\(=2x-1\)

Answer 2

[KAl(SO4)2·12H2O]

a) (x + 2)(x - 2) - (x - 3)(x + 1)

= x² - 4 - x² + 2x + 3

= 2x - 1

b) (2x + 1)² + (3x - 1)² + 2.(2x + 1)(2x - 1)

= 4x² + 4x + 1 + 9x² - 6x + 8x² - 2 

= 21x² - 2x