What's the coefficient of the x^2 y^4 term in the expansion of (x + y)*6*(3x - 2y)*(5x + y)^4?
Using brute force , which is something you should NOT do (even though this time, I'm just lazy):
\(11250x^6 + 12750(x^5)(y) - 1800(x^4)(y^2) - 4740(xy)^3\)\( - 1662(x^2)(y^4)-234(x)(y^5) - 12y^6\)
\(\text{The coefficient of} (x^2)(y^4) \text{ is -1,662.}\)
Hope this helped .