Find the product:

$(3 x-5 y+4)\left(9 x^{2}+25 y^{2}+15 x y-20 y+12 x+16\right)$

$=(3 x+(-5 y)+4)\left(9 x^{2}+25 y^{2}+16+15 x y-20 y+12 x\right)$

$(a+b+c)\left(a^{2}+b^{2}+c^{2}-a b-b c-c a\right)=a^{3}+b^{3}+c^{3}-3 a b c$

Here, $a=3 x, b=-5 y, c=4$

$(3 x+(-5 y)+4)\left(9 x^{2}+25 y^{2}+16+15 x y-20 y+12 x\right)$

$=(3 x)^{3}+(-5 y)^{3}+4^{3}-3 \times 3 x(-5 y)(4)$

$=27 x^{3}-125 y^{3}+64+180 x y$