Diketahui x-y = 4 , x³-y³ = 28 maka nilai xy = .... (sertakan cara)

Mapel Matematika
Bab Pemfaktoran

x^3 - y^3 = 28
(x - y)(x2 + y^2 + xy) = 28
4((x - y)^2 + 2xy) + xy) = 28
4(4^2 + 3xy) = 28
64 + 12xy = 28
12xy = -36
xy = -3

x³ - y³ = 28
( x - y ) ( x2 + y² + xy ) = 28
4(( x - y )² + 2xy ) + xy )) = 28
4( 4² + 3xy ) = 28
64 + 12xy = 28
12xy = 28 - 64
12xy = -36
xy = -36/12
xy = -3 [tex] [/tex]