Factorise (4 – x)2 – 2x

(i) x(12x + 7) – 10

(ii) (4 – x)² – 2x

Answer :

(i) x(12x + 7) – 10

Above terms can be written as,

12x² + 7x – 10

12x² + 15x – 8x – 10

Take out common in all terms we get,

3x(4x + 5) – 2(4x + 5)

(4x + 5) (3x – 2)

(ii) (4 – x)² – 2x

(4 – x)² – 2x

We know that, (a – b)² = a² – 2ab + b²

So, (4² – (2 × 4 × x) + x²) – 2x

16 – 8x + x² – 2x

x² – 10x + 16

x² – 8x – 2x + 16

Take out common in all terms we get,

x(x – 8) – 2(x – 8)

(x – 8) (x -2)