We are to find the roots of the quadratic equation at the denominator.
i.e.
x²+x-2 = x² + 2x - x - 2
= x(x+2) - 1(x+2)
= (x -1 ) (x + 2)
Thus;
b)
The quadratic equation roots can be calculated by finding two numbers that if we multiply then, we will get -54 and if we add or subtract them, we will get -3