Question

solve using identity
a. 61×59
b. (9x-1) (9x-1)​

Answer 1

Step-by-step explanation:

a. 61 × 59

= (60+1) × (60-1)

formula used (a + b)(a - b) = a² - b²

hence, 60² - 1² = 3600 - 1 = 3599 ans.

b. (9x - 1)(9x - 1)

Formula used (a - b)(a - b) = a² - 2ab + b²

hence, (9x)² - 2(9x)(1) + (1)²

= 81x² - 18x + 1 ans.