My Math Forum  

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

Algebra Pre-Algebra and Basic Algebra Math Forum


Thanks Tree1Thanks
  • 1 Post By skipjack
Reply
 
LinkBack Thread Tools Display Modes
April 18th, 2017, 02:15 PM   #1
Senior Member
 
Joined: Oct 2013
From: New York, USA

Posts: 537
Thanks: 77

How Do You Write A Generic Form Of This Equation?

My dad gave me the problem:

Square root of (x + 15) + Square root of x = 15

x = 49, with the equation simplifying to 8 + 7 = 15. In general, the constant term, which in this case is 15 is 2*(square root of x) + 1. If the constant term decreased by 2 to 13, x would decrease by 13 to the next lower square number. If you call y the constant term, write an identity using x and y.
EvanJ is offline  
 
April 18th, 2017, 03:37 PM   #2
Global Moderator
 
Joined: Dec 2006

Posts: 17,728
Thanks: 1359

There are numerous identities that use x and y. It's unclear what is expected.
Thanks from topsquark
skipjack is online now  
April 19th, 2017, 02:58 AM   #3
Member
 
Joined: Mar 2017
From: Tasmania

Posts: 36
Thanks: 2

assuming x is still 49 the equation is y = real answer (in this case 15) + (x-(real answer)) (0.062)

y= 15+(x - 15)(0.059)


(0.059) to get this just take 2 equations then find difference of y

Last edited by Posher; April 19th, 2017 at 03:02 AM.
Posher is offline  
April 19th, 2017, 02:12 PM   #4
Global Moderator
 
Joined: Dec 2006

Posts: 17,728
Thanks: 1359

That doesn't make sense to me.

The problem seems to say that y = 2√x + 1 is what in general makes the original equation true.

They may be hinting at the identity x + y ≡ (√x + 1)²,
because that's equivalent (if x is non-negative) to √(x + y) ≡ √x + 1,
which is equivalent to √(x + y) + √x ≡ 2√x + 1,
which is equivalent to the original equation if y = 2√x + 1.

However, that makes no use of the remarks about decreasing the value of y, which themselves require that x is a perfect square, so that "the next lower square number" (than x) is meaningful.
skipjack is online now  
Reply

  My Math Forum > High School Math Forum > Algebra

Tags
equation, form, generic, write



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
write complex number in a+bi form with a and b real wortel Complex Analysis 2 October 31st, 2016 08:51 PM
write radical expression in simplest form mick7 Algebra 1 July 19th, 2015 08:41 AM
write equation MathNewb42 Applied Math 0 March 12th, 2013 06:53 AM
write as an equation? vivalajuicy Linear Algebra 3 November 13th, 2012 06:33 AM
Write inequality in the form a < x < b jaredbeach Algebra 5 September 8th, 2011 08:06 PM





Copyright © 2017 My Math Forum. All rights reserved.