American ll Math olympiad problem

[@CabezaDePercebe]

At 6:30, the ecuation is : v² - 20v +1 = 0. Still, the values for a, b and c are correct.

[@user-nr6rr8yj6x]

Good❤

[@heenapathan4700]

V2-19v 7.35 minutes equations not satisfied -20v+v will e subtract . In this equation c=0

[@alaeddinemustapha8496]

Error in solution at 6.17 min1/v×v = 1 not v.

[@haiderlughmani]

Yes! its mistake 😊

[@nasrullahhusnan2289]

Equation v²+v=20v at 6:15 is incorrect. Supposedly it is v²+1=20v

[@user-ye7de2en6s]

There is a mistake. The answer same, but negative.

[@haiderlughmani]

Where? I chucked step by step its correct throughout.

[@canvadesigner_616]

❣

[@lewistsao3279]

There is no check if 10-sqrt(11) is positive. Not obvious with casual inspection (needs calculator, old fashioned log table not precise enough)

[@danieldepaula6930]

An easy way to verify that is squaring both numbers and comparing them.
(10)² = 100
(3sqrt(11))² = 9*11 = 99
100 > 99, therefore, 10 > 3sqrt(11). Then, 10-3sqrt(11) is positive.

[@lewistsao3279]

Ah yes of course. It's been over 40 years since I last dabbled in mental gymnastics and had forgotten all these tricks 😢

[@LongLe-wx4uk]

A^n=1/a^-n (5/2)^x=1/(5/2)^-x

[@haiderlughmani]

In denominator power should be negative.

[@LongLe-wx4uk]

🤨

[@cubemind9877]

It's Ans is 1

[@haiderlughmani]

?

[@cubemind9877]

Because I take log both side

[@2012tulio]

You joking?

[@keroppikeroppi6572]

5:54 1/V x V = V ?