Question

lf4x-5y=7andxy=-2find64x³-125y³​

Answer 1

(a-b)³=a³-b³-3ab(a+b)

(4x-5y)³=64x³-125y³-3×4×5xy(4x-5y)

7³=64x³-125y³-60×(-2)(7)

64x³-125y³=343-840=-497

Answer 2

Answer:

see answer

Step-by-step explanation:

here the formula

a 3 − b 3 = (a − b) (a 2 + a b + b 2 )

we can find answer on putting the values in this formula

(4x-5y)³=64x³-125y³-3×4×5xy(4x-5y)

7³=64x³-125y³-60×(-2)(7)

64x³-125y³=343-840=-497