
PreCalculus PreCalculus Math Forum 
 LinkBack  Thread Tools  Display Modes 
April 22nd, 2018, 05:32 PM  #1 
Newbie Joined: Apr 2018 From: Australia Posts: 1 Thanks: 0  Require some help/advice on this question
I’ve attached the question below. I would love for anyone to assist me thanks urgently .

April 22nd, 2018, 07:23 PM  #2 
Senior Member Joined: May 2016 From: USA Posts: 1,210 Thanks: 498 
Do you understand why they say to consider the corresponding equalities? If you say $x + y < 2$, then the region where that is true is everything under and to the left of the line $x + y = 2.$ If you say $x + y > 2$, then the region where that is true is everything over and to the right of the line $x + y = 2.$ Do you understand that? If so, all you need to do in this problem is to graph the equalities related to each inequality, determine what region is indicated by the inequality, and find the region where they all overlap. To get you started, the inequalities $x \ge 0 \text { and } y \ge 0$ have the corresponding equalities $x = 0 \text { and } y = 0$, namely the x and y axis, and the region indicated by the > is above the x axis and to the right of the yaxis. Clear now? 
April 28th, 2018, 12:16 PM  #3 
Math Team Joined: Jan 2015 From: Alabama Posts: 3,261 Thanks: 894 
The first inequality is $\displaystyle 2x+ y\le 21$. As JeffM1 told you, that is bounded by the equality $\displaystyle 2x+ y= 21$. When x = 0, that becomes y = 21 so mark the point (0, 21). When y= 0, that becomes 2x = 21 so x = 21/2 = 10 and 1/2. Mark the point (21/2, 0). A line is determined by two points, so the graph of all (x, y) that satisfy 2x + y = 21. The set of all (x, 6) that satisfy $\displaystyle 2x+ y\le 21$ is that lie together with all points below and to the left (that set contains (0, 0), which obviously satisfies 2x + y < 21).
Last edited by skipjack; April 28th, 2018 at 10:30 PM. 
April 28th, 2018, 02:42 PM  #4  
Math Team Joined: May 2013 From: The Astral plane Posts: 1,922 Thanks: 775 Math Focus: Wibbly wobbly timeywimey stuff.  Quote:
Dan Last edited by skipjack; April 28th, 2018 at 10:33 PM.  
April 28th, 2018, 02:55 PM  #5 
Math Team Joined: Jul 2011 From: Texas Posts: 2,785 Thanks: 1434  

Tags 
help or advice, question, require 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Hello, I am currently studying for an undergrad scholarship. I require some help.  Aleramos  Academic Guidance  3  May 22nd, 2016 06:12 AM 
Does solving systems of differential equations require linear algebra?  petermojer  Differential Equations  1  July 1st, 2014 05:51 AM 
I require your assistance with math!  Algeria  Academic Guidance  4  June 19th, 2014 09:32 AM 
Need advice  WickedJack  New Users  3  October 22nd, 2011 05:54 PM 
require a value of h such that sin(x) equals for x  maximus101  Calculus  3  March 8th, 2011 11:51 AM 