If M - N = -2 and M3 - N3 = -26, Find Mn.

If m - n = -2 and m³ - n³ = -26, find mn.

Sum

m - n = -2, m³ - n³ = -26
(m - n)³ = m³ - n³ - 3mn (m - n)
⇒ (-2)³ = -26 - 3mn (-2)
⇒ 6mn
= - 8 + 26
= 18
⇒ mn = 3.

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Chapter 3: Expansions - Exercise 4.2

Chapter 3 Expansions
Exercise 4.2 | Q 21

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