Neha notices that for p(x) = x^2 - 4x + k, the two zeroes are equal (the graph just touches the x-axis). What must be the value of k?

Question

Accepted Answer

4. Equal zeroes mean discriminant = 0: b^2 - 4ac = 16 - 4k = 0, so k = 4. Then x^2 - 4x + 4 = (x - 2)^2, a double zero at 2.

Neha notices that for $p (x) = x^{2} - 4 x + k$ , the two zeroes are equal (the graph just touches the $x$ -axis).
What must be the value of $k$ ?