Question

find the value of 64 x cube + 125 y cube is 4 x + 5 Y is equals to 19 and x y is equals to 5​

Answer 1

in 3rd step use the formula of (a+b)^3

the answer is 1159

Answer 2

Answer:

1159

Step-by-step explanation:

Given :

4x + 5y = 19,

xy = 5,.

To find :

The value of 64x³ + 125y³

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We know that,

(a + b)³ = a³ + b³ + 3ab(a+b)

substituting the values as,

a = 4x, b = 5y,

We get,

⇒ (4x + 5y)³ = (4x)³ + (5y)³ + 3(4x)(5y)(4x + 5y)

⇒ (4x + 5y)³ = 64x³ + 125y³ + 60xy(4x + 5y)

By substituting 4x + 5y = 19 & xy = 5,

We get,

⇒ (19)³ = 64x³ + 125y³ + 60(5)(19)

⇒ 6859 = 64x³ + 125y³ + 5700

⇒ 6859 - 5700 = 64x³ + 125y³

⇒ 64x³ + 125y³ = 1159

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                      Hope it Helps!!