Question

(a) Expand and simplify (a×a) – (a - b)(a + b).

(b) Hence write down the value of
(6730×6730) – 6728 x 6732 without using a
calculator.​

Answer 1

a) b²

b) 4

Step-by-step explanation:

a) (axa)=a²

(a-b)(a+b) = a²-b²

So it's a²-(a²-b²) = b²

b)

Let a be 6730

(axa) - (a-2)(a+2)

since b =2 and a²-(a²-b²) = b²,

(6730x6730) - 6728 x 6732 = 2² = 4