Germany | A Nice olympiad Exponential math Equation solve? X^2 -X^3 =80 |

[@AshiKhan-kh7ed]

🤯😬😬😬😬😬😬🤪🤪🤪🤪🤪

[@kajalbanerjee8220]

Minus 4

[@ngocdo5687]

X^2 - X^3 = 80, X = ? *. 80 = 16 + 64 = 4x4 + 4x4x4 ** X = 4 ./.

[@b213videoz]

1:41 You did the right thing - of course, but completely failed to explain the intent, that is WHY you did what you did. Your HOW you did it was fairly poor too. That, by the way, is one of the trickiest part of this problem - yes it's basic stuff but only once you know what you are doing and why. Many of your viewers could be lost, I would have been lost for sure 1.5 years ago 😂 I mean is your video just a mere showing off of you solving stuff OR are your videos to help those that got stuck and explain to them well so that they can finally get it and get unstuck ?

[@AlexanderSemashkevich]

(-4)²-(-4)³=16-(-64)=16+64=80 So x= -4

[@b213videoz]

x² - x³ - 80 = 0 x² - 4² - x³ - 4³ = 0 (x² - 4²) - (x³ + 4³) = 0 (x-4)(x+4) - (x³ + 4³) = 0 (x-4)(x+4) - (x+4)(x²+4²-4x) = 0 (x+4)(x-4 - (x²+4²-4x)) = 0 (x+4)(x-4 - x² -16 + 4x) = 0 (x+4)(-x² + 4x + x -4 - 16) = 0 (x+4) = 0, x1 = -4 (-x² + 5x -20) = 0 let's get rid of that -x by multiplying the whole equation by -1: x² - 5x + 20 = 0 D = b² - 4ac = (-5)² - 4·1·20 = 25 - 80 = -55 ...those "imaginary numbers", I can't be bothered with those - go solve yourself 🤪 On second thought I decided to do it: 5 +/- i*sqrt(55) x2, x3 = ---------------------------- 2