Question

If a-b=6 and ab=20, find the value of a³-b³.

Answer 1

Given : a - b = 6 and ab = 20

On Cubing a - b = 6 both sides, we get :  

(a - b)³ = (6)³

By Using an identity :  (a - b)³ = a³ - b³ - 3ab(a - b)

(a)³– (b)³ – 3 ab (a – b) = 216

 a³ - b³ – 3 × 20 (6) = 216

[a - b = 6  and ab = 20]

a³ - b³ - 360 = 216

a³ - b³ = 216 + 260

a³ - b³ = 576

Hence, the value of a³ - b³ is 576.

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If a-b=-8, and ab =-12, then a³ – b³ =

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Answer 2

Answer:

please let me know for any other quires good luck buddy:)

Step-by-step explanation:

given a-b=6, ab=20

a^3-b^3

=>(a^2+b^2+a*b) (a-b)

=>((a-b)^2+2*ab +a*b) (a-b)

=>((a-b)^2+3*ab) (a-b)

=>6(36 +3(20))

=>6*96

=576