Question

what x²-y²+4y³-5x³(64-xy) = ? if (x=39) (y=63)​

Answer 1

Answer:

Correct option is

A

0

We know that,

a  

3

+b  

3

+c  

3

=(a+b+c)(a  

2

+b  

2

+c  

2

−ab−bc−ca)+3abc

If a+b+c=0, then a  

3

+b  

3

+c  

3

=3abc

Now, given x  

3

+y  

3

−12xy+64 and  

      x+y=−4

   =>x+y+4=0  

Here, a=x, b=y, c=4 and a+b+c=x+y+4=0

Therefore

x  

3

+y  

3

+64=3xy(4)

                         =12xyz

Now,

x  

3

+y  

3

+64−12xyz=12xyz−12xyz

                                       =0

Step-by-step explanation:

Answer 2

Step-by-step explanation:

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