(2x+根号x)2*(2x+根号x)2
=(4x^2+4x*根号x+x)*(4x^2+4x*根号x+x)
=16x^4+16x^3*根号x+4x^3
+16x^3*根号x+16x^3+4x^2*根号x
+4x^3+4x^2*根号x+x^2
=16x^4+32x^3*根号x+24x^3+8x^2*根号+x^2
所以 x3的系数是24