Question

factorize the folloeing expressions using suitable agebraic identity
$81 - 18y + {y}^{2}$
​

Answer 1

Answer:

(9 - y)²

Step-by-step explanation:

To factorise:

81 - 18y + y²

Method to factorise:

Since the terms on both ends of the expression are perfect squares, we can factorise it using the following identity:

(a - b)² = a² - 2ab + b²

⇒ (9)² - 2(9)(y) + (y)²

⇒ (9 - y)²

More identities:

• (a + b)² = a² + 2ab + b²

• a² - b² = (a + b)(a - b)

• (x + a)(x + b) = x² + x(a + b) + ab

Hope it helps!