(a+b) (a-b)

3. (x+y)(u-v) = xu-xv+yu-yv
for all positive numbers
x, y, u, v with u>v

4. The product of
the sum and
difference of two
positive numbers
is the difference
of their squares.

5. The difference of
the squares of two
positive numbers is
the product of their
sum and difference.

6. (x+y)(x-y)=x²-y²
For all positive
numbers x,y with
x>y

7. x²
(x+y)(x-y)
x
x
y² y
x
x-y
y
X²-y²
x
x-y
x+y

8. THANK YOU