Question

a) If 2x – 4y = 5 and xy = 3,
find 8x3 - 64y3

Answer 1

665

Step-by-step explanation:

27x3 – 64x3 = (3x)3 – (4y)3

= (3x – 4y)3 (3x – 4y)3 + 3 (3x)(4y) (3x – 4y)

[∵ a3 – b3 = (a – b)3 + 3ab(a – b)

= (5)3 + 36(xy) (3x – 4y) = 125 + 36 (3) (5)

= 125 + 540

Answer 2

Answer:

485

Step-by-step explanation:

it is the correct answer