Question

factorise it

49-81x^2​

Answer 1

Answer:

Rewrite 49 as 72 . Rewrite 81x2 81 x 2 as (9x)2 ( 9 x ) 2 . Since both terms are perfect squares, factor using the difference of squares formula, a2−b2=(a+b)(a−b) a 2 - b 2 = ( a + b ) ( a - b ) where a=7 and b=9x b = 9 x

Answer 2

Answer:

-1 (9x+7)(9x-7)

Step-by-step explanation:

49-81x^2

= -81x^2+49

= -1 (81x^2-49)

= -1 {(9x)^2-(7)^2}

= -1 (9x+7)(9x-7) [a^2-b^2=(a+b)(a-b)]