Answer: 428
Explanation:
This is a substitution problems,
Just substitute for the values of x and y , multiply them out and add.
Here we go;
5x³ + 4y³
= 5(4³) + 4(3³)
= 5( 4 x 4 x 4 ) + 4( 3 x 3 x 3)
= 5 x 64 + 4 x 27
= 320 + 108 add directly or find the common factor
= 4(80 + 27)
= 4(107)
= 4 x 107
= 428