Learn how to solve quadratic equations like x^2=36 or (x-2)^2=49.
Log in ragnarbacon21 8 years agoPosted 8 years ago. Direct link to ragnarbacon21's post “what do you do if you hav...” what do you do if you have a hard time remembering big formulas? • (29 votes) Ali Mürteza Yeşil 8 years agoPosted 8 years ago. Direct link to Ali Mürteza Yeşil's post “Create random codes that ...” Create random codes that will be easier to remember. For example "Q = I x t" is formula for charge used in a circuit for a given time. I call it "Quit" where Qu is Charge, i is Current and t is time. (75 votes) Purple 8 years agoPosted 8 years ago. Direct link to Purple's post “Wouldn't expanding the pa...” Wouldn't expanding the parenthesis make it easier? For example: (x-2)^2 = 81 be x^2- 2^2=81, thus making it easier to solve? • (17 votes) Isabella Mathews 4 years agoPosted 4 years ago. Direct link to Isabella Mathews's post “No! `(x-2)² = (x-2)(x-2) ...” No! Hope this helps! :) Steph Lugosi 8 years agoPosted 8 years ago. Direct link to Steph Lugosi's post “when looking at the quadr...” when looking at the quadratic equation with the (x-#)^2 • (16 votes) Jesus fan a year agoPosted a year ago. Direct link to Jesus fan's post “i wish people were on the...” i wish people were on these when i am i feel like im always a little behind, if anyone is out there, i would like to talk. yours truly, baconator • (18 votes) Emily Henry a year agoPosted a year ago. Direct link to Emily Henry's post “yo im here” yo im here (7 votes) Ayush Barik 5 years agoPosted 5 years ago. Direct link to Ayush Barik's post “"Note that every positive...” "Note that every positive number has two square roots: a positive square root and a negative square root. For example, both 6 and -6 when squared, equal 36. Therefore, this equation has two solutions." In my calculator I tried squaring -6 but I got -36? • (9 votes) SgtOddball 4 years agoPosted 4 years ago. Direct link to SgtOddball's post “I know you posted this a ...” I know you posted this a while ago and may not see this but: Your calculator (like mine) interprets "-6", as "-1 * 6". If you want to square a negative number, then type "(-6)^2", which the calculator interprets as "(-1 * 6)^2", meaning it preforms the multiplication before squaring the number. I hope that helped. (20 votes) jonahmolina90 8 years agoPosted 8 years ago. Direct link to jonahmolina90's post “for the very last challen...” for the very last challenge question: how does the equation go from x^2 + 8x + 16 --> (x + 4) ^2 ? is it because 4*4 = 16 and 4+4=8 thus, (x+4)^2 ? • (10 votes) Kim Seidel 8 years agoPosted 8 years ago. Direct link to Kim Seidel's post “Yes. If you factor x^2 +...” Yes. If you factor x^2 + 8x + 16 it becomes (x + 4)(x + 4), which is the same as (x + 4) ^2 (14 votes) FECHERSHILOH a year agoPosted a year ago. Direct link to FECHERSHILOH's post “Help. I hate math. The la...” Help. I hate math. The last time someone has ever ask a question was 7 years ago. I don't understand the bottem part of this page. its 2023 • (11 votes) Kim Seidel a year agoPosted a year ago. Direct link to Kim Seidel's post “The site defaults to show...” The site defaults to show top rated questions/answers first. To see the recent questions, select "recent" as the sort sequence. (5 votes) moyed 8 years agoPosted 8 years ago. Direct link to moyed's post “Do you always work on th...” Do you always work on the left side of the equal sign first in problems like the challenge question? • (8 votes) Blaze 8 years agoPosted 8 years ago. Direct link to Blaze's post “You don't need to... but ...” You don't need to... but it kind of goes over there later. (5 votes) Uri 8 years agoPosted 8 years ago. Direct link to Uri's post “So I did most of the vide...” So I did most of the videos prior to this point but I still don't understand what a quadratic is or more specifically, how it differs from a polynomial. • (5 votes) Kim Seidel 8 years agoPosted 8 years ago. Direct link to Kim Seidel's post “A quadratic is a polynomi...” A quadratic is a polynomial that (when simplified) can be written in the form: Ax^2 + Bx + C where A can not = 0. If it is a quadratic equation, then it would be: Ax^2 + Bx + C = 0. So what does all that mean... a quadratic is a polynomial that has 1, 2 or 3 terms, but the highest degree term will have a variable that is squared. (13 votes) Anais Ruiz 8 years agoPosted 8 years ago. Direct link to Anais Ruiz's post “What is the best way to t...” What is the best way to tell the difference between the functions, and when to use which one? • (7 votes) Beorn MacRupert 8 years agoPosted 8 years ago. Direct link to Beorn MacRupert's post “Which functions, exactly?...” Which functions, exactly? Please, be more specific and maybe I can help you! (2 votes)Want to join the conversation?
Build your own logic that makes no sense. Australia has more letters than Europa, so it cannot fit in Europa. Australia is not located in Europa.(x-2)² = (x-2)(x-2) = x²-2x-2x+4 = x²-4x-4
That means, now you gotta solve for x²-4x+4 = 81.x²-4x+4 = 81 (splitting the middle term)
x²-4x+4-81 = 81-81
x²-4x-77 = 0
x²-11x+7x-77 = 0x(x-11)+7(x-11) = 0(x+7)(x-11) = 0 (factoring out (x-11))
Using the zero product property,x = -7 or x = 11
This way, as you can see, is much, much longer than the square root method. Why bother going the long way, when you can have the solution in just a few seconds?
what if the ^2 was next to the (x) in the equation?
Meaning it interprets "-6^2" as "-1 * 6^2", and since calculators obey the order of operations, it squares the 6 first, then multiplies that by -1.
There are many polynomials that are not quadratics. For example: 3x + 7 = 0 is a polynomial equation. However, it can not be written in the form Ax^2 + Bx + C =0 because there is no "x^2" term. Thus, it is not a quadratic. Instead, 3x + 7 = 0 is a simple linear equation (or 1st degree equation) that can be solved without using quadratic methods
2nd example: x^3 + 5x^2 + 6 =0 is a 3rd degree polynomial equation, however it is not a quadratic because the highest degree term is x^3 (not x^2). You will learn that equations like this can sometimes be solved using a combination of quadratic methods (e.g., factoring is used to get down to a lower degree: X ( X^2 + 5X + 6) = 0. We now have 2 factors, where one is a quadratic and you could use an appropriate quadratic method to solve that factor).
Hope this helps.
