Germany | Can you solve this ? | Nice Math Olympiad Algebra Problem

[@ichdu6710]

I've seen this trick very often on YT in the last months. really no one uses a very easy method to solve such an equation of third degree after multiplying the equation with -1 we receive: x³ - x² + 80 = 0 by inspection we found, that one solution is x = -4 Therefore x³ - x² + 80 = (x+4)(x² + ax + 20) the variable a can be found by comparing left and right side by writing the right side without the brackets

[@Studentofgreatmagadh]

I'm first here! 🥰

[@learncommunolizer]

🎉 Thank you very much!

[@davidcase4600]

You don't justify breaking 80 into 16 and 64. Why not 50 and 30. Using the answer we could guess is not math

[@GladysDiku-kh6lc]

5√4+y

[@thomasharding1838]

you had the answer at 1 minute 20 seconds. X =-4 -4 times -4 =16. -4 times -4 times -4 = -64. 16 - (-64) =80 (not easy to type out clearly) He was just fitting in numbers to make it work, like @robertloveless4938 said. After all -15 plus -65 also equals -80 but that doesn't work in the equation. You either have to guess -4 or just keep trying numbers until it works.

[@МихаилЧугунов-ю5я]

сразу понятно, что Х должен быт отрицательным чётным числом: минус четыре: 16+64.

[@MathSync]

i ❤ Mathematics

[@marynjoroge5088]

I can’t do it

[@marynjoroge5088]

Please I have never done these maths so remove it from me am understanding nothing

[@robertloveless4938]

I cheated. I immediately knew x had to be negative, then I plugged in numbers, starting with -3 (answer =36), and worked the numbers. . Fortunately, I didn't have to go past 4.

[@thomasharding1838]

You cheated no more than "Learncommunolizer did ! He had to know that X equaled -4 to plug in his equation at the 1:20 ish point. But YES, it was clear it had to be negative.

[@АлексейК-э1п]

1 минута на подумать.

[@Mal1234567]

x^2 - 3^2 = 79; solve for x. No calculators please.

[@mohamedzafir8566]

Square root of 70?

[@Mal1234567]

@@mohamedzafir8566 Sorry, I mean to write X^3 - X^2 = 79

[@Mal1234567]

Too easy. Solve X^3 - X^2 = 79 using REAL algebra.

[@GladysDiku-kh6lc]

4+y✓5+y

[@yapadek3098]

sqrt(negative number)... When I was young I could be killed for this.

[@miracbarsapaydn650]

X = -4

[@user-do5rq1yb3t]

-4

[@オサムン-y8q]

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