Week 6 in Precalc 11 – [Solving Quadratic Equations Using Factoring]

This week in Precalculus 11, I learned how to factor quadratic equations and the differences between quadratic and linear equations.

So first of all, for linear equations, x will never have a power. Quadratic equations will always have a power.

For example, $latex x^2+5x+6=0 is a quadratic equation and 2x+6=0 is a linear equation.

Let’s get into factoring the quadratic equations.

Let’s start with a simple equation that has already been factored. In the example below, we want the left side of the = to be the same as the right side by finding the value of x. With some simple calculations, we know that if x is the conjugate of one of the number in one of the brackets, the bracket will equal 0, and the brackets are multiplied by each other so if one bracket is equal to 0 we know that the left side of the equals sign would be 0.

In the example below, we have one more step before solving which is to factor out the equation. As seen in one of my previous, we want the product of c, sum of b so we take the factors of 15 which are 1,5 and 3,5, our b value is 8 so 1 and 5 won’t work since it would equal 6 but 3,5 will work since it adds up to our B value of 8. We should also know that the variables will be in the beginning of our brackets and our original equation is x^2 and we know that x multiplied by x equals latex x^2. So the values in our brackets will be (x+5)(x+3). We can verify this by foiling the equation and seeing if it matches up with out original equation as seen in the image which it does. We then repeat the steps in the previous example.

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