Question

hi,


${8a}^{3} - {64b}^{3} \: if \: 2a \: - 4b \: = \: 1 \: and \: ab \: = \: 2$

pls solve this fast as u can !

Answer 1

Answer:

8a³ - 64b³ = 49

Step-by-step explanation:

Given Equation is 2a - 4b = 1

on cubing both sides, we get

⇒ (2a - 4b)³ = 1³

⇒ 8a³ - 64b³ - 3(2a)(4b)(2a - 4b) = 1

⇒ 8a³ - 64b³ - 24ab(1) = 1

⇒ 8a³ - 64b³ - 24(2) = 1

⇒ 8a³ - 64b³ - 48 = 1

⇒ 8a³ - 64b³ = 49.

Hope it helps!

Answer 2

Step-by-step explanation:

Given Equation is 2a - 4b = 1

on cubing both sides, we get

(2a - 4b)³ = 1³

8a³ - 64b³ - 3(2a)(4b)(2a - 4b) = 1

8a³ - 64b³ - 24ab(1) = 1

8a³ - 64b³ - 24(2) = 1

8a³ - 64b³ - 48 = 1

8a³ - 64b³ = 49.