Step-by-step explanation:
what do we need to do ? just do the multiplications (and squaring is also a multiplication, just by itself) ?
we could do the exercise in full or just remember the results of
(a-b)² = (a-b)(a-b) = a² - 2ab + b²
and
(a+b)(a-b) = a² - b²
so, we get
x² - 2x + 1 + x² - 1
simplifying this is
2x² - 2x = 2(x² - x) = 2x(x - 1)
