Evaluate 211 *189 by using suitable identity
Answers
Answered by
6
Heya !!!
Given :---
211 × 189....
Let us first break it .....
(200 + 11) (200 - 11)..... ....(i)..
Now, think of an identity......
Well....
It is
(x + a)(x+b) = x² + (a+b)x + ab..... ....(ii).
Comparing equation i and ii, we get...
x = 200.
a = 11, and
b = -11.
So,
211×189 = (200 + 11)(200-11)
= 200² + (11-11)200 -11(11)
= 40000 - 121
= 39879. .....(iii).
We can verify this.....
211 × 189 = 39879. ....(iv).
As, equation iii and iv are equal.
Hence, we got the right answer.
Hope it helps
Given :---
211 × 189....
Let us first break it .....
(200 + 11) (200 - 11)..... ....(i)..
Now, think of an identity......
Well....
It is
(x + a)(x+b) = x² + (a+b)x + ab..... ....(ii).
Comparing equation i and ii, we get...
x = 200.
a = 11, and
b = -11.
So,
211×189 = (200 + 11)(200-11)
= 200² + (11-11)200 -11(11)
= 40000 - 121
= 39879. .....(iii).
We can verify this.....
211 × 189 = 39879. ....(iv).
As, equation iii and iv are equal.
Hence, we got the right answer.
Hope it helps
Similar questions