Question

Find the values of a and b so that (x + 1) and (x - 1) are factors of x + ax - 3x² + 2x + b. -​

Answer 1

Let f(x) = x4 + ax3 − 3x2 + 2x + b be the given polynomial. By factor theorem, (x+1)and (x-1)are the factors of f(x) if f(−1) and f(1) both are equal to zero. Hence, the value of a and b are – 2 and 2 respectively. Concept: Factorising the Quadratic Polynomial (Trinomial) of the type ax2 + bx + c, a ≠ 0.