My Math Forum  

Go Back   My Math Forum > High School Math Forum > Elementary Math

Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion


Thanks Tree2Thanks
  • 2 Post By skipjack
Reply
 
LinkBack Thread Tools Display Modes
December 11th, 2018, 01:19 PM   #1
Senior Member
 
Joined: Dec 2015
From: iPhone

Posts: 444
Thanks: 68

sqrt equation

$\displaystyle \sqrt{5-x}=5-x^2$
idontknow is offline  
 
December 11th, 2018, 01:58 PM   #2
Global Moderator
 
Joined: Dec 2006

Posts: 20,388
Thanks: 2015

Squaring gives $5 - x = 25 - 10x^2 + x^4$, so $x^4 - 10x^2 + x + 20 = 0$.

Hence $(x^2 - x - 4)(x^2 + x - 5) = 0$.

After solving that, check which of its roots satisfy the original equation.
Thanks from topsquark and idontknow
skipjack is offline  
December 11th, 2018, 02:23 PM   #3
Senior Member
 
Joined: Dec 2015
From: iPhone

Posts: 444
Thanks: 68

I didnt notice that squaring gives a prod
idontknow is offline  
December 11th, 2018, 02:45 PM   #4
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 14,148
Thanks: 1004

What's a "prod"?
Denis is offline  
December 11th, 2018, 02:56 PM   #5
Senior Member
 
Joined: Dec 2015
From: iPhone

Posts: 444
Thanks: 68

Edit it , i meant product
idontknow is offline  
Reply

  My Math Forum > High School Math Forum > Elementary Math

Tags
equation, sqrt



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Simpler solve for this equation: sqrt(x^2-x-10)-sqrt(x^2-11x)=10 DecoratorFawn82 Algebra 2 October 1st, 2017 06:03 PM
Consider the demand equation p = sqrt((200-x)/(2x)) Lalaluye Calculus 2 July 3rd, 2017 07:52 PM
(sin(x)+log(x)+sqrt(x))' ungeheuer Calculus 1 August 30th, 2013 04:34 AM
Lim of sqrt (1-cos(x)) / x when x---> 0? abypt Real Analysis 2 November 8th, 2009 04:45 PM
simplifying sqrt[a + sqrt(b)] nikkor180 Real Analysis 3 June 25th, 2009 03:18 AM





Copyright © 2019 My Math Forum. All rights reserved.