It would have been easier if in the beginning you subtracted the sqrt(X) from both sides of the equation and then squared both sides. This would have led to less math.

Very nice recalling our memories of maths while in school/college

25 by trial and error. No math needed.

Would be much easier to subtract the square root of x from both sides.

Good. I'm curious to know in what practical situation in real life we ​​can arrive at an equation like this and many others that you have already solved on the channel. Can you give us a practical example of this particular equation in real life? Greetings from Brazil!

simply take sqrt(x) to the other side square both sides, you will get x-9=81-18Sqrt(x)+x 18Sqrt(x)= 90 SQRT(x)=5 x=25

Thank you. But we can do it a little differently. 1) We substitute instead of ‘x’ - squares of numbers. We easy to find the root of equation: x=25. 2) f(x)=sqrt(x)+sqrt(x-9) is an increasing function. So , it takes all its values only once . That’s enough . And that’s Your answer. Another solution. (1) sqrt(x)=u>=0 , (2) sqrt(x-9)=v>=0 . (3) u+v=9 , (4) u^2-v^2=9. So : [u^2-v^2]/[u+v]=9/9 ; (5) u-v=1 . (u+v)+(u-v)=9+1 . (6) u=5>=0 .v=9-5=4>=0 . We substitute (6) in (at ?) (1) . We get Your answer. With respect , Lidiy

asnwer=3 os isit

Красиво !

@learncommunolizer

Ай бұрын

Thank you very much!

easiest

X=25

Neden bu kadar uzun bir işlem 🤔

X=25