Question

if 3x-2y=11 and xy=-1 find 27x³-8y³

Answer 1

Hey dear,
Your answer is $\bold\boxed{1133}$

Using the identity,

(a - b)³ = a³ - b³ - 3ab(a - b)


Putting 3x as a and 2y as b we get and cubing both sides we get

(3x - 2y)³ = (11)³

=> (3x)³ - (2y)³ - 3(3x)(2y)( 3x - 2y) = 1331

=> 27x³ - 8y³ - 3(6xy)(11) = 1331
[since 3x - 2y is given as 11)

=> 27x³ - 8y³ - 3[6 × (-1)](11) = 1331
(since XY is given as -1)

=> 27x³ - 8y³ -3(-6)(11) = 1331

=> 27x³ - 8y³ + 18(11) = 1331

=> 27x³ - 8y³ + 198 = 1331


=> 27x³ - 8y³ = 1331 - 198

=> 27x³ - 8y³ = 1133


Hope it helps dear friend ☺️

Answer 2

Hy friend plz see the attachment.....☺️

Hope it will help uh☺️

Be brainly......☺️

@Soma❤️