Question

Factories the following
a)21x^2+5x-6
b)a^9-b^9​

Answer 1

Step-by-step explanation:

a)21x²+5x-6=21x²+14x-9x-6=7x(3x+2)-3x(3x+2)=(7x-3x)(3x+2)

b)a^9-b^9=(a³-b³)(a^6+a³b³+b^6)=

(a-b)(a²+ab+b²)(a^6+b^6+a³b³)

Answer 2

GIVEn

Factories the following

a)21x^2+5x-6

b)a^9-b^9

SOLUTIOn

• 21x² + 5x - 6

★ Splitting middle term

→ 21x² + 14x - 9x - 6

→ 7x(3x + 2) - 3(3x + 2)

→ (3x + 2)(7x - 3)

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• a^9 - b^9

★ Apply identity :

a³ - b³ = (a - b)(a² + ab + b²)

→ (a³)³ - (b³)³

→ (a³ - b³)[(a³)² + a³*b³ + (b³)²]

→ [(a³ - b³)][a^6 + a³b³ + b^6]

→ [(a - b){(a)² + a*b + (b)²}][a^6 + a³b³ + b^6]

→ (a - b)(a² + ab + b²)(a^6 + a³b³ + b^6)

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