Question

find the value of 27x^3+8y^3 if 3x+2y=20 and xy=11/9​

Answer 1

Answer:

Step-by-step explanation:

We know that

a^3 + b^3 = (a + b)^3 + 3ab(a + b)

Now, We set our question to this formula,

(3x)^3  + (2y)^3 = (3x + 2y)^3 + 3*3x*2y(3x + 2y)

(3x)^3  + (2y)^3 = (20)^3 + 18(11/9)(20)

(3x)^3  + (2y)^3 = 8000 + 440

(3x)^3  + (2y)^3 = 8440

Hence, (3x)^3  + (2y)^3 is 8440.