## How to use a quadratic equation calculator?

Calculator Use This online calculator is a quadratic equation solver that will solve a second-order polynomial equation such as ax 2 + bx + c = 0 for x, where a ≠ 0, using the quadratic formula. The calculator solution will show work using the quadratic formula to solve the entered equation for real and complex roots.

**What does ± mean in a quadratic equation?**

About the Quadratic Formula Plus/Minus. First of all what is that plus/minus thing that looks like ±? The ± means there are TWO answers: x = −b + √(b 2 − 4ac) 2a. x = −b − √(b 2 − 4ac) 2a. Here is an example with two answers: But it does not always work out like that! Imagine if the curve “just touches” the x-axis.

**Is the quadratic formula in Khan Academy useful?**

We’re not big fans of you memorizing formulas, but this one is useful (and we think you should learn how to derive it as well as use it, but that’s for the second video!). Then the formula will help you find the roots of a quadratic equation, i.e. the values of where this equation is solved.

### Do you know the derivation of the quadratic formula?

Only the use of the quadratic formula, as well as the basics of completing the square will be discussed here (since the derivation of the formula involves completing the square). Below is the quadratic formula, as well as its derivation.

**Which is the answer to the quadratic equation T = 3?**

The “t = 3” is the answer we want: The ball hits the ground after 3 seconds! Some interesting points: (−0.2,0) says that −0.2 seconds BEFORE we threw the ball it was at ground level. This never happened! So our common sense says to ignore it. (3,0) says that at 3 seconds the ball is at ground level.

**How does the quadratic formula calculator calculate the discriminant?**

Calculator determines whether the discriminant (b2 − 4ac) is less than, greater than or equal to 0. When b2 − 4ac = 0 there is one real root. When b2 − 4ac > 0 there are two real roots. When b2 − 4ac < 0 there are two complex roots.

## What happens if you watch a quadratic formula?

Videos you watch may be added to the TV’s watch history and influence TV recommendations. To avoid this, cancel and sign in to YouTube on your computer. An error occurred while retrieving sharing information. Please try again later. Learn all about the quadratic formula with this step-by-step video lesson: