If the graph of is tangent to the -axis, what is the value of ?

Answer and explanation

Correct answer: C.

.
.
  1. Step 1: A parabola is tangent to the -axis if and only if the equation has exactly one repeated real root, meaning its discriminant is zero ().
  2. Step 2: Compute the discriminant with , , and constant :
  3. Step 3: Solve for :
Answer
.

Practise more Quadratic Functions and Coordinate Geometry.

Free questions with an explanation for every one, and full timed EJU Japan mock tests.