3 ms·
If b is negative, define c = -b, and use the linked result to show that a^2 - b^2 = a^2 - (-c)^2 = a^2 - c^2 = (a + c)(a - c) = (a + b)(a - b)
by chisquared 2y ago
If b is negative, define c = -b, and use the linked result to show that
a^2 - b^2 = a^2 - (-c)^2 = a^2 - c^2 = (a + c)(a - c) = (a + b)(a - b)