how to find x intercept of a quadratic function

Find Vertex and Intercepts of Quadratic Functions - Calculator

An easy to use calculator to find the vertex, x and y intercepts of the graph of a quadratic function and write the function in vertex form.

f(x) = ax² + bx + c

Vertex of the graph of a Parabola

The vertex of the graph of a parabola is the maximum or minimum point of the graph. This online calculator uses the formulas
h = - b / 2a
and
k = f(h)
to find the x and y coordinates h and k,respectively, of the vertex of a parabola.

parabola, x and y intercepts and vertex. — Figure 1. Graph of a parabola with x (points A and B) and y (point C) intercepts and the vertex V.

x and y intercepts of the graph of a Parabola

To find the x intercepts, the calculator solves the quadratic equation ax ² + bx + c = 0 using the quadratic formulas:
x1 = (- b + √Δ) / (2 a)
x2 = (- b - √Δ) / (2 a)
where Δ = b ² - 4 a c is the discriminant.
The y intercept if given by f(0) = c.

Use of Calculator to Find Vertex and Intercepts of Quadratic Functions

1 - Enter the coefficients a, b, c as real numbers and the number decimal places as an integer and press "Solve". The coordinates of the x and y intercepts are displayed. If the two coordinates are equal, the graph touches the x axis and the two x intercepts have equal x coordinates. The x intercepts may not exist. The x and y coordinates of the vertex and the vertex form of the function are also displayed at the bottom.