Quadratic Formula Tutorial

Many people in this generation are doing well in their school classes and expect things to continue going their way. But when they arrive to their math class and they have a pop quiz on the quadratic formula, they have no idea how to do it. This is a tutorial on the quadratic formula and how and when to use it. First off, if you do not now what a trinomial is, please look it up and learn all about it before you attempt the quadratic formula. The quadratic formula is this:

Many people also know what the quadratic formula is, but they do not know when to use it. This is when you use it. So when a trinomial is not factorable, for example: 1X^2+14x+542=0. This trinomial is not factorable because the 14 and the 542 do not have any common multiples. Basically, the numbers that you can multiply to get 542, added together, do not equal 14. This is when you would use quadratic formula.

When you look at the quadratic formula, all you would see is the letters, or variables. These variables stand for the coefficients of the numbers in the trinomial (1X^2+14x-542=0). The "a" of the quadratic formula would be the first coefficient in the trinomial, or 1, since the coefficient of X^2 (x squared) is 1. The "b" of the quadratic formula would be 14, since the coefficient of x is 14. The final variable, "c", is the regular number, -542. Now all you have to do is plug in the coefficients to the formula and solve for x.

x = -b ± √(b^2 - 4ac) / 2a

x= -14 ± √14^2 - 4(1)(-542) / 2(1)

x= -14 ± √196 + 2168 / 2

x= -14 ± √2364 / 2

x= -14 ± 48.6209831246 / 2

x= -7 ± 24.3104915623

Now, x can either be 17.3104915623 or -31.3104915623 (if you are trying to find the length of a segment, the answer would be the positive option since a segment length cannot be negative).

I would suggest attempting to make your own problems and practicing the formula with them. This way you get a better handle of the concept of this formula. If you are still confused, please watch the video below.

https://www.khanacademy.org/math/algebra/quadratics/solving-quadratics-using-the-quadratic-formula/v/using-the-quadratic-formula

Created By
David McDonough
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