Question

evaluate 211x189 by using suitable identidy​

Answer 1

Answer:

use identity

$(a) ^{2} - (b)^{2} = \: (a + b) \: (a + b)$

then put like this:-

$211 \times 189 \: (given) \\ then \: if \: we \: consider \: a = 200 \: and \: \\ b = 11 \: we \: get \: \\ \\ (200 + 11) \: (200 - 11) \: or \: according \: to \: the \: formula \: we \: get \: \\ \\ \\ (200)^{2} - (11)^{2} = \: 40000 - 121 = 39879.$