Question

factorise: x-2y-x^2+4y^2​

Answer 1

$x - 2y - x {}^{2} + 4y {}^{2}$

$= x - 2y - (x {}^{2} - 4y {}^{2})$

$= x - 2y - (x - 2y)(x + 2y)$

$= (x - 2y)(1 - (x + 2y)$

$= (x - 2y)(1 - x - 2y)$

Answer 2

x−2y−x

2

+4y

2

x−2y−(x

2

+(2y)

2

)

we know that a

2

−b

2

=(a+b)(a−b)

x−2y−[(x+2y)(x−2y)]

Take out common in all terms,

(x−2y)(1−(x+2y))

(x−2y)(1−x−2y)