中四續多項式，數學，幫幫我，THANK^_^

1 代 x = 2﹐2^3 + 3(2) + a = 0

a = -14

2 3x = A(x - 1)(x + 2) + B(x - 2)(x + 2) + C(x + 1)(x - 1)

代x = 1 => 3 = B(-1)(3) => B = -1

代x = -2 => -6 = C(-1)(-3) => C = -2

代x = 0 => 0 = -2A - 4B - C => 2A = -4B - C = 6 = > A = 3

city u computing maths