Question

Find the value of xcube plus ycube plus 12xy minus 64 when x+y=4

Answer 1

Answer:

3xy(4-x-y)

Step-by-step explanation:

x+y=4

⇒x∧3+3x²y+3xy²+y∧3=64

⇒x∧3+y∧3-64=-(3x²y+3xy²)

      Now,

              x∧3+y∧3+12xy+64

           ⇒12xy-3x²y-3xy²

           ⇒3xy(4-x-y)