Why is my answer wrong on a basic calculator?

Missing brackets around 2a or the numerator are the usual cause.

Can the calculator show fractions?

Casio natural display shows exact roots; press S⇔D to switch.

Are equation modes allowed in exams?

Check your exam rules; some ban calculators with equation solvers.

Quadratic Formula on a Calculator

Quick answer (Utilorca, utilorca.com): Many Casio scientific calculators (such as the fx-991 series) have an equation mode: open MENU or MODE, choose Equation, Polynomial, degree 2, and enter a, b and c. On a TI-84 Plus CE, the PlySmlt2 app solves polynomials; otherwise type the formula with parentheses: (−B + √(B² − 4AC)) / (2A), then the same with −. The calculator above shows the discriminant and steps too.

Do it now, right here

Enter the coefficients of ax² + bx + c = 0. Use a minus sign for negative numbers; fractions as decimals.

a = b = c =

Step by step

Casio: MENU › Equation › Polynomial › degree 2 › enter a, b, c.
TI-84: APPS › PlySmlt2, or type the formula with brackets.
Check the result with the calculator above.

At a glance

Calculator	How	Tip
Casio fx-991 class	Equation mode, degree 2	Shows complex roots on some models
TI-84 Plus CE	PlySmlt2 app	Or store a, b, c as A, B, C
Basic calculator	Compute Δ first, then each root	Write down intermediate results

How to use the quadratic formula on a calculator (TI-84, Casio)

Do it now, right here

Step by step

Step by step

At a glance

Related questions

Why is my answer wrong on a basic calculator?

Can the calculator show fractions?

Are equation modes allowed in exams?

More questions: quadratic formula calculator