Question

if 4x- 3y =13 and xy= 14 then find the value of 64x3- 27y3=?

Answer 1

Step-by-step explanation:

xy=14

then

x=14/y or y=14/x

put the value of x and y in eq. 4x-3y=13

I am putting y = 14/x

4x-3 (14/x) =13

4x-42/x=13

4x-42=13×x

4x-42=13x

4x+13x=42

17x=42

x=42÷17

x=2.47

round off it to 2.50 y=14÷2.50

y=5.6

xy= 14

2.50×5.6=14

put value of x and y in eq. (64x3-27y3)

= 64×2.50×3-27×5.6×3

=480-453.6

=26.4 ans:-)

Answer 2

Step-by-step explanation:

4x^3 - 3y^3 = (a-b)^3 + 3ab(a-b)

64x3 - 27y3 = 13^3 + 3×14×13

64x3 - 27y3 = 2197 + 6552

64x3 - 27y3 = 8749

So,the answer for this question is 8749.