(5a^2 b - 3bc^2)^4

$$\\(5a^2 b - 3bc^2)^4\\\\ =^4C_0(5a^2b)^4+^4C_1(5a^2b)^3(-3bc^2)^1 +^4C_2 (5a^2b)^2 (-3bc^2)^2 +^4C_3(5a^2b)^1 (-3bc^2)^3 +^4C_4(-3bc^2)^4\\\\ =(5a^2b)^4+4(5a^2b)^3(-3bc^2)^1 +6 (5a^2b)^2 (-3bc^2)^2 +4(5a^2b)^1 (-3bc^2)^3 +(-3bc^2)^4\\\\ =(625a^8b^4)+4(125a^6b^3)(-3bc^2)+6 (25a^4b^2)(9b^2c^4)+4(5a^2b)(-27b^3c^6) +(81b^4c^8)\\\\ =(625a^8b^4)-(1500a^6b^4c^2)+(1350a^4b^4c^4)-540(a^2b^4c^6)+(81b^4c^8)\\\\ =625a^8b^4\;-\;1500a^6b^4c^2\;+\;1350a^4b^4c^4\;-\;540a^2b^4c^6\;+\;81b^4c^8\\\\$$