Do you like Completing the Square method or the Quadratic Formula?

[UsagiFlapmaster_Arisu]

The way he writes is soo satisfying and sounds like asmr but very useful method

[shannonmcdonald]

If the b term is an even number, i prefer CTS; if its uneven, Quadratic Formula to avoid fractions.

[Mayank]

easiest way to solve quadratic equation 👍

[Mycroft]

For anyone who does not get the joke, they are the same method:

ax^2 + bx + c = 0
ax^2 + bx = -c
x^2 + bx/a = -c/a
x^2 + bx/a + (b^2)/(4a^2) = -c/a + (b^2)/(4a^2)
[x + b/(2a)]^2 = (b^2 – 4ac)/(4a^2)
x + b/(2a) = ±[(b^2 – 4ac)^(1/2)]/(2a)
x = [-b ± (b^2 – 4ac)^(1/2)]/(2a)

Also, if the b is odd, multiply in a 4 then add b^2

x^2 – 13x + 5 = 0
x^2 – 13x = -5
4x^2 – 52x = -20
4x^2 – 52x + 169 = -20 + 169
(2x – 13)^2 = 149
2x – 13 = ±149^(1/2)
2x = 13 ± 149^(1/2)
x = [13 ± 149^(1/2)]/2

[Gbhmagic]

I like the formula.. its just one thing to remeber and if you do these infrequently...and to be honest i have never ran into one even in electronics..a formual is way easier to remember over the long term.

[MonsterERB]

For those not aware, take a general quadratic equation in the form of ax^2 + bx + c = 0. Solve for x by completing the square and you get... the quadratic equation. So even "I'll take the easy way and use the quadratic equation" is just "I am completing the square, just skipping some steps and jumping to the end". Usually I find completing the square is faster anyway, and I don't have to worry I remembered the equation incorrectly.

[nighttrain]

I prefer to complete the square because I can retain the solution as a surd and avoid messy decimals. Also, it helps to work out the turning point.

[quinn]

That middle step is slightly over complicated, if you write it out fully it is simpler to under stand.

x² - 12x + 5 = 0
(x-12/2)² - 36 +5 = 0 {Drop down the sign separating the first two terms into the bracket and then minus from the outside of the bracket half of the coefficient
of the second term squared}
(x-6)²-31=0
(x-6)² = 31
{Sqrt}
x-6 = ±√31
x = 6 ± √31
(x-6)²

[AbcdAbcd-pe]

On comparing x²-12x+5=0 with ax²+bx+c=0, we get a=1, b=-12, c=5
》x=(-b±(b²-4ac)½)/2a
x= ( -(-12)±((-12)²-4(1)(5))½ )/2(1)
x= (12±124½)/2
x=6±31½

[xaimeglez]

That was Where you when I was going to high school?!?!?!? Great video,

[dougr.]

You could add that both roots are positive. (By inspection!)

[Tim-Kaa]

Why 12 / 2 and then raised into power?

[greego]

Why have I never learned this. This makes a lot of sense. This does require a little more thinking as you need to figure out how to complete the square so I can see how the quadratic formula is better for some people but for me this seems better.

[okaro]

That is best solved with the pq-formula.

[Mohshad]

But why it is not applicable on other type of quadratic equations 😢😢😢

[NinjaBear]

If a=1 or a and b are both perfect squares, then I will use completing the square. If not, then i will use the quadratic formula.

[Brid]

If I get a quadratic equation ax^2 + bx + c = 0 and it is not factorable, I would use CTS only when a=1
I can let go of b being even, but a not being one makes this a tedious task

[sparkyheberling]

Isn’t the Quadratic Formula the same as completing the square?

[therealmagmalord]

I learned completing the square once, my teacher hated it so we avoided it. Now it looks so useful.

[Angelo]

Why use two to divide the 12x? Is it because we’re simplifying the process or is there something I’m missing can someone explain plain lease