Welcome to understanding the quadratic formula! This powerful tool helps us solve quadratic equations.The quadratic formula is one of the most important equations in algebra.This formula works for any quadratic equation that's written in standard form: a x squared plus b x plus c equals zero.Let's understand what each letter represents in a quadratic equation.The letter 'a' is the coefficient of x squared. It's the number in front of x squared.'b' is the coefficient of x, the number in front of x to the first power.And 'c' is the constant term, the number with no variable.Let's look at some examples to practice identifying these values.In the equation x squared plus five x plus six equals zero, a is one because there's no number in front of x squared.b is positive five, the coefficient of x.And c is positive six, our constant term.Let's look at another example: two x squared minus three x minus one equals zero.Here, a is two.b is negative three, notice the minus sign is important.And c is negative one.Here's a tricky one: three x squared plus two equals zero.a is three.b is zero because there is no x term.And c is positive two.Now that we can identify a, b, and c in any quadratic equation, we're ready to learn how to use them in the formula.We'll substitute our values into the quadratic formula using our example equation.From our equation, we can identify that a equals 1, b equals 5, and c equals 6.Let's begin by substituting these values into the formula. We replace b with 5, a with 1, and c with 6.Now let's calculate b squared, which is 5 squared, giving us 25.Next, we calculate 4ac, which is 4 times 1 times 6, giving us 24.Subtracting 4ac from b squared gives us 25 minus 24, which equals 1.Let's substitute these calculations back into our equation.This simplifies to the square root of 1 under the radical.The plus-minus symbol means we'll need to calculate two different versions: one adding and one subtracting.In our next section, we'll solve for both the positive and negative cases to find our two solutions.Now that we have our solutions, let's verify them and understand what they mean.Let's verify that x equals negative two is a solution by plugging it back into our original equation.Similarly, let's verify x equals negative three.These solutions have a geometric meaning. Let's look at the graph of our quadratic equation.The parabola represents our quadratic equation. The solutions we found are the x-intercepts - the points where the parabola crosses the x-axis.The number of solutions a quadratic equation has depends on its discriminant - the expression b squared minus four a c.When the discriminant is positive, like in our example, we get two real solutions. When it's zero, we get one solution. And when it's negative, we get no real solutions.Let's look at some examples of each case.
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