Question

Simplify using ifentity :- 68×72. Second question:- simplify using identity:- 93 square

Answer 1

Hlo friend.. Cutiepie Here..

Here is ur answer :

(1) 68 × 72

✴️(70 - 2) (70 + 2)

✔️Using identity (a-b) (a+b) = a² - b²

✴️(70)² - (2)²

✴️4900 - 4

➡️4896


(2) 93²

✴️(100 - 7)²

✔️Using identity ( a- b)² = a² + b² - 2ab

✴️(100)² + (7)² - 2× 100×7

✴️10000+ 49 - 1400

✴️10049 - 1400

➡️8649

HOPE IT HELPS YOU...

REGARDS
@sunita

Answer 2

(i)68×72
we can write it as:
(70 - 2) (70 + 2)
We know,
(a+b) (a-b) = a² - b²
= (70)² - (2)²
= 4900 - 4
= 4896

(ii) (93)²
we can write it as,
(90+3)²
we know,
(a + b)² = a² + b² + 2ab
= (90)² + (3)² + 2 × 90×3
=8100 + 9 + 540
= 8649