Answer:
=(s^2 - t^2)/4
Step-by-step explanation:
a + b = s and a - b = t,
Add the two equations together
a + b = s
a - b = t
----------------
2a = s+t
a = (s+t)/2
Subtract the two equations
a + b = s
- a + b = -t
-------------------
2b =(s-t)
b = (s-t)/2
We want to find ab
ab = (s+t)/2 * (s-t)/2
FOIL
=(s^2 - t^2)/4
