Math, asked by Army2417, 6 months ago

(a+b)(a-b)=a2-b2:evaluate 19×21

Answers

Answered by studyhard2005
0

Answer:

399

Step-by-step explanation:

19 × 21

= (20 - 1)(20 + 1)

= (20)² - (1)²

= 400 - 1

= 399

Answered by austinvictor2006
0

(20 - 1)(20 + 1)

20² - 1²

400 - 1

= 399

HOPE IT HELPS.......

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