Question

6.
9z^2-x^2-4xy-4y^2​

Answer 1

Step-by-step explanation:

x

2

+4y

2

−9z

2

−4xy

=(x

2

+4y

2

−4xy)−9z

2

=[x

2

+(2y)

2

−(2×x×2y)]−9z

2

=(x−2y)

2

−9z

2

(∵(a−b)

2

=a

2

+b

2

−2ab)

=(x−2y)

2

−(3z)

2

=(x−2y−3z)(x−2y+3z)(∵a

2

−b

2

=(a−b)(a+b))

Hence, x

2

+4y

2

−9z

2

−4xy=(x−2y−3z)(x−2y+3z).