Question

1). Find the value of 64x³— 125z³ if 4x—5z=16 and xz=12.​

Answer 1

Answer:

15616

Step-by-step explanation:

From given problem we have to find the value of 64x³ - 125z³

Given (4x — 5z) = 16, xz = 12

On cubing both sides of (4x — 5z) = 16 we get

(4x — 5z) ³ = (16)³

We shall use identity

(a - b)³ = a³ - b³ - 3ab (a - b)

4x³ - 125z³ - 3(4x)(5z) (4x - 5z)

64x³- 125z³ - 60(xz)(16) = 4096

64x³- 125z³ - 60(12)(16) = 4096

64x³ - 125z³ - 11520 = 4096

64x³ - 125z³ = 4096 + 11520

64x³ - 125z³ = 15616

Hence the value of 64x³ -- 125z³ is .

1 5616.