Question

Was the expression a^2-b^2 = (a+b)(a-b) invented or discovered?

Answer 1

Answer:

the expression is invented

Answer 2

I would say it was discovered.
Expanding (a + b)(a - b)
= a(a - b) + b(a - b)
= a^2 - ab + ba - b^2
= a^2 - b^2
So factorising the difference between two squares simply reverses the equation