Question

27. Evaluate {(405)2 – (395)?}.​

Answer 1

Answer:

Using a

2

−b

2

=(a+b)(a−b)

⇒{(405)

2

−(395)

2

}=(405+395)(405−395)

=(800)×(10).

Hence, the answer is (800)×(10).

Answer 2

answer is 8000

as (a+b)(a-b) rule will.be used

(400+5) (400-5)

400+400 × 5+5

800×10

= 8000