If a polynomial is divisible by 
, then 
is a root of this polynomial.
Here (x-a) is equal to x+2:
So -2 is a root of the polynomial. That means <span>x³-6x²+kx+10</span>=0 for x=-2. Now substitute -2 for x in the equation and solve for k:
Here (x-a) is equal to x+2:
So -2 is a root of the polynomial. That means <span>x³-6x²+kx+10</span>=0 for x=-2. Now substitute -2 for x in the equation and solve for k: