CalculationTime

Quadratic Formula Calculator

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Your numbers, formula and explanation together

Quadratic Formula Calculator: x = 2 or 1. Discriminant 1; roots = (-b ± √discriminant) ÷ 2a. Vertex (1.5, -0.25).

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

x = (-b ± √(b² - 4ac)) ÷ 2a. Discriminant D = b² - 4ac. Vertex x-coordinate = -b ÷ 2a.
  1. Apply the formulax = (-b ± √(b² - 4ac)) ÷ 2a. Discriminant D = b² - 4ac. Vertex x-coordinate = -b ÷ 2a.x = 2 or 1Discriminant 1; roots = (-b ± √discriminant) ÷ 2a. Vertex (1.5, -0.25).

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

a coefficient
1
The coefficient on x^2. Use a nonzero value for a true quadratic.
b coefficient
-3
The coefficient on x.
c coefficient
2
The constant term.
Decimal places
4
Controls displayed rounding for roots and checks.

Resulting answer

x = 2 or 1

Discriminant 1; roots = (-b ± √discriminant) ÷ 2a. Vertex (1.5, -0.25).

Answer
x = 2 or 1
Live support
Discriminant 1; roots = (-b ± √discriminant) ÷ 2a. Vertex (1.5, -0.25).

Assumptions used

What this answer assumes

Best for homework checks, algebra worksheets and quick root verification where the discriminant and formula should stay visible.

  • Inputs are numeric coefficients in ax² + bx + c = 0.
  • If a is zero, the page falls back to the linear equation bx + c = 0.
  • Negative discriminants are shown as complex conjugate roots.
  • Displayed roots are rounded; formula steps keep the coefficient trail visible.

Master’s Tip

How to use the result well

Master’s Tip: check the discriminant first. Positive means two real roots, zero means one repeated real root, and negative means a complex pair.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

a coefficient
1
The coefficient on x^2. Use a nonzero value for a true quadratic.
b coefficient
-3
The coefficient on x.
c coefficient
2
The constant term.
Decimal places
4
Controls displayed rounding for roots and checks.

What-if check

Discriminant-first proof

The discriminant decides the root type before the quadratic formula is evaluated, so the printout preserves that checkpoint.

CheckValueNote
a, b, c1, -3, 2quadratic coefficients
discriminant1two real roots
vertex x1.5-b divided by 2a
current outputx = 2 or 1formula result

Visual proof

Result path

InputMethodAnswerx = 2 or 1

Discriminant 1; roots = (-b ± √discriminant) ÷ 2a. Vertex (1.5, -0.25).

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Formula

x = (-b ± √(b² - 4ac)) ÷ 2a. Discriminant D = b² - 4ac. Vertex x-coordinate = -b ÷ 2a.

Worked example

For x² - 3x + 2 = 0, D = (-3)² - 4(1)(2) = 1. Roots are (3 ± 1) ÷ 2, so x = 2 or x = 1.

Professional note

Master’s Tip: check the discriminant first. Positive means two real roots, zero means one repeated real root, and negative means a complex pair.

Regional and unit assumptions

Standard or basis: ordinary real/complex algebra for second-degree polynomial equations; no curriculum-specific rounding rule is claimed.

Assumptions and limitations

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

x = (-b ± √(b² - 4ac)) ÷ 2a. Discriminant D = b² - 4ac. Vertex x-coordinate = -b ÷ 2a.

Standard or basis

Standard or basis: ordinary real/complex algebra for second-degree polynomial equations; no curriculum-specific rounding rule is claimed.

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Master’s Tip: check the discriminant first. Positive means two real roots, zero means one repeated real root, and negative means a complex pair.

Questions

What is the quadratic formula?

The quadratic formula is x = (-b ± √(b² - 4ac)) ÷ 2a for equations written as ax² + bx + c = 0.

What does the discriminant tell me?

The discriminant b² - 4ac tells whether the roots are two real roots, one repeated real root, or a complex pair.

What if a equals zero?

Then the equation is not quadratic. This page solves the remaining linear equation when b is not zero.

Calculation note

Quadratic equations connect algebra, geometry and graphing. The discriminant and vertex make the answer more useful than a bare pair of roots.

The discriminant is the first checkpoint

Before calculating roots, the discriminant explains the shape of the answer. It prevents confusion when a calculator returns complex values.

The vertex explains the graph

The same coefficients also define the parabola vertex. Showing it beside the roots helps connect equation solving to graph behavior.