Quadratic Formula – MOST COMMON MISTAKES!

How to use the Quadratic Formula correctly.

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[nyneeveanya]

You missed my group of people who watch your videos. Retired senior citizens who like math and use these videos to help keep our minds sharp. Most of your videos I’ve watched I figured out. This not so much as I initially forgot the quadratic formula when you have a negative b and negative c. Then forgot to factor for 48 to reduce more. I will now go practice this type problem more. Thankyou.❤❤❤

[bharatrajpara]

nearing 70 and refreshing my math skills.Thanks

[bigdog]

rewrite as y = x² - 4x - 8. Now that we have it in the form y = ax² + bx + c. -8 * 1 and -4 * 2 = -8 neither combo add to -4 so we can not factor.
we can place this equation into the form of y = a(x-h)² + k where h = 1/2(-b/a) and k = -a (h²) + c. The a, b, c terms are the same as defined by the quadratic form

h = 1/2(4/1) = 4/2 or just 2
k = -1(2²) - 8 = -4 - 8 or just -12
now we have the h and k values we plug them in
y = (x-2)² - 12
solve with the formulas y = h + √(-k/a) and y = h - √(-k/a) [The ( ) is used to show the k and a terms are under the root symbol]

y = 2 + √(12/1) and y = 2 - √(12/1)

y = 2 + 2√3 and y = 2 - 2√3

Way easier than remembering that clunky formula and also you will learn this formula anyways when trying to graph a parabola. the answers for x are the coordinates where the parabola intersect with the x axis. (read as first x solution, 0 and second x solution, 0. But ONLY if a real number was given as the solutions)

The c term is the y intercept and read as [0, c]. and finally the vertex is our [h, k] coordinates which are actually read as [x, y] coordinates.

Long story short if a teacher has you graph a quadratic equation, the above is how it is done.

[russelllomando]

got it. and after 55+ years, I still remember that formula. thanks.

[manuelgarrido]

When b is an even number, then I use de formula from Po-Shen-Loh : x=-b/2a +- sq((b/2)²-ac) instead of the quadratic formula.

[newstarcadefan]

Quadratic equations are quite the logic puzzles if you think about it. If you take your time an think things through slowly you will get the correct answer. This is why teachers demand that work must be shown in case you make a mistake.

[samswift]

X=5.51 rounded to 2 decimal places. I had to use pen and paper for this one

[missrobinsmath]

Another common mistake is forgetting the negative with the a, b, c

[chocolateangel]

Am I the only one that finds the Quadratic Formula annoying (can't stand the reduction of it all). I would rather Complete The Square, using the Equating Coefficients method or use the Po-Shen Loh method. Who's with me?

[laurindapace]

Balance is special. A quadratic equation is special if this is set to zero

[laurindapace]

Pop quiz answer is called the discriminant

[terry_willis]

"Quad" means four. So why isn't the highest power in a quadratic equation 4? X^4 instead of X^2.

[martinfiedler]

Mmmh. The tedious chore of simplifying...
I stopped at the square root of 12. 🤕

[ItsVideos]

At 9:22 you say "x - 6". Should say "x - 3".

[vespa]

27:25 Made exactly the same error myself (the +2, -2)

[NabihHechme]

Just solve the formula , too much complicatins