设 f(x) = ax^2 + bx + c ,
a(x+1)^2 + b(x+1) + c + a(x-10)^2 + b(x-10) + c = 2x^2 - 4x,
化简,对应系数相等,
2a = 2,-18a + 2b = 4,101 a - 9 b + 2 c = 0
解得
a = 1,b = 11,c = -1,
所以 f（x）的解析式为
f(x) = x^2 + 11x - 1