Add maths (rationalise the denominator)

If x = a is a zero of the polynome x^3 + x + 10, rationalise the denominator of 1 / (a - 3).

If x = a is a zero of the polynome x^3 + x + 10, then
a is a solution to the equation x^3 + x + 10 = 0, or
a^3 +a + 10 = 0
Solving the equation analytically, we get
a=-2, 1-2i or 2i+1
where i is the complex number sqrt(-1).

The expressions 1/(a-3) would therefore be
1/(-2-3)=1/5, or
1/(1-2i-3)=-/2(i+1)=-(i-1)/2((i+1)(i-1))=-(i-1)/2(-2)=(i-1)/4, or
1/(2i+1-3)=/2(i-1)=(i+1)/2((i-1)(i+1))=-(i+1) /4

AMath 新sy唔學complex number