In this clip we're going to learn how to solve the quadratic formula. Now the quadratic formula is used to solve a quadratic equation. Here's a quadratic equation. How do I know it's quadratic equation? The highest power of X is 2. First step: get your A, your B, and your C. Your A is 1, which is the number in front of the X squared, which if there's no number there is always assumed to be one. This is your B, and this is your C. That's where you get this from. Without this, you won't be able to use the formula. Write down the quadratic formula, here it is right here. I suggest you do the next step. Open up the parentheses for every letter that you see. Do that, okay? And then fill in your parentheses as you can see in this step. Fill in your A, your B, and your C. Once you do that, work it out. This stays the same, negative three. Three to the second is nine. Negative four times 1 times negative ten is plus forty. Watch your signs at this step, most people mess up right here, okay? Nine plus four is forty nine, so you have the square root forty nine. Notice that these two numbers stay the same down here. The square root of forty nine is seven. Plus and a minus. I divided them here. And then three and seven is four divided by two is two. Negative three, negative seven is two, divided it's negative five. There's your two answers on how to solve that quadratic equation.
