Question

(19.9)²
EVALUTE THE FOLLOWING BY IDENTITY a-b²=a²-2ab+b²​

Answer 1

Answer:

(a-b)² = a² + b² - 2ab

(19.9)² can be written as

(20 - 0.1)²

Now using given identity

(20 - 0.1)² = (20)² + (0.1)² - 2× 20 × 0.1

= 400 + 0.01 - 4

= 400.01 - 4

= 396.01. Ans