Question

Find the value of 8x 3 + 27y 3 if 2x +3y =8 and xy = 5.

Answer 1

Answer:

8x³ + 27y³ = -208

Explanation:

It is given that,

2x+3y = 8 ------(1)

xy = 5 -----(2)

Now ,

8x³ + 27y³

= (2x)³+(3y)³

= (2x+3y)³-3×(2x)×(3y)(2x+3y)

= 8³-18×(xy)×8

= 512-18×5×8

= 512-720

= -208

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