Question

if p-q = -8 , pq = -12 , then find the value of p3 - q3

Answer 1

Answer:

p³ - q³ = -224

Step-by-step explanation:

Given that,

p-q = -8, pq = -12, p³-q³ = ?

⇒ p³ - q³ = (p-q)³ + 3pq(p-q)

(∵ (a-b)³ = a³ - b³ - 3ab(a-b) ⇒ a³ - b³ = (a-b)³ + 3ab(a-b) )

⇒ p³ - q³ = (-8)³ + 3(-12)(-8)         (∵Given)

⇒ p³ - q³ = -512 + 3(12×8)

⇒ p³ - q³ = -512 + 3(96)

⇒ p³ - q³ = -512 + 288

⇒ p³ - q³ = -224

∴ p³ - q³ = -224

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