Question

(α-β)²=(α+β)²-4αβ how????

Answer 1

What is (a-b)^2?
(a-b)^2 = a^2 - 2ab + b^2.......(1)

And what is (a+b)^2 - 4ab
= a^2+2ab+b^2 - 4ab
= a^2 - 2ab + b^2
= ( a- b)^2
from equation 1

Thus,
(a-b)^2 = (a+b)^2 - 4ab

Answer 2

I am taking alpha and beta as a and b
$(a-b)^{2}$= $a^{2}$ – 2ab + $b^{2}$
given=>(a+b)²-4ab=$a^{2}$ + 2ab +$b^{2}$-4ab  =$a^{2}$+$b^{2}$-4ab

                 =$(a-b)^{2}$