Question

explain that a^2- b^2= (a+b)(a-b)
you can change the left hand side only.

Answer 1

axa become a square +and- become - and bxb become bsquare so a^2-b^2 is equal to (a+b) (a-b)

Answer 2

If you use the method of FOIL (first term, outer term, inner term, last term) to solve the given operation on the left hand side you will end up with what is given on the right side.

(a-b)(a+b)= a×a+b×a-b×a-b×b

This will give us
a²+ba-ba-b²
Positive and negative get cancelled, i.e. -ba and +ba get cancelled and we are left with
a²-b².

I hope this helps