Question

What is the area of a²- 4b² if the value of a=4, and b=1?

Answer 1

Answer:

a²-4b²

or ( a-4b) ²

by using the identity ( a-b) ² = a²+ b²- 2 ab

or 4²+1²-2×4× 1

or 16+1-8

or 17-8

or 9