Question

The graph of the polynomial f(x) = ax² + bx + c is as shown in Fig. 2.20. Write the value of b² − 4ac and the number of real zeros of f(x).

Answer 1

The graph of the polynomial f(x) = ax² + bx + c or the curve touches x−axis at point `((-b)/2a,0)`. The x-coordinate of this point gives two equal zeros of the polynomial and `b^2 -4ac =0`.

Hence the number of real zeros of  `f(x)`is 2 and  `b^2 - 4ac = 0`