Question

factorise (9x^2+42x+49)^2-y^4​

Answer 1

Answer is in the pic.

hope it will help you !

Answer 2

Answer:

(9x^2 + 42x + 49)^2 - y^4

= (9x^2 + 42x + 49)^2 - (y^2)^2

= (9x^2 + 42x + 49 + y^2)(9x^2 + 42x + 49 -y^2)

[a^2 - b^2 = (a+b)(a-b)]

={(3x + 7)^2 + y^2}{(3x + 7)^2 - y^2}

={(3x + 7)^2 + y^2}{(3x + 7- y)(3x + 7 +y)}

={(3x + 7)^2 + y^2}(3x + 7- y)(3x + 7 +y)

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