Question

(x-1).(x+1)-2.(x+4).(x-4)

Answer 1

(x-1).(x+1)-2.(x+4).(x-4)
x² + x - x - 1 - 2.(x² - 4x + 4x - 16)
x² + x - x - 1 - 2x² + 8x - 8x + 32
x² - 2x² + x + 8x - x - 8x - 1 + 32
- x² + 9x - 9x + 31      cancela + 9x - 9x
- x² + 31