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October 9, 2015
Posted by **Hello Kitty** on Thursday, October 13, 2011 at 1:24pm.

Hello Kitty!

- Algebra 1 -
**Angel**, Thursday, October 13, 2011 at 1:28pm1.

◦1

Graph a single equation to see at a glance what the value of the equation is for many different points. An equation that shows how pressure varies with temperature becomes a lot more meaningful when it is graphed. By looking at the graph, you can instantly see what the pressure is for any temperature. You can also quickly see what temperature corresponds to critical pressures -- like the maximum pressure that a container is supposed to reach. You can also see regions where the equations as "less than" or "greater than" a value -- the line is the boundary between these two regions. For example, y = 3x + 5 is a straight line. All the points below the line are points where 3x + 5 < y and all the points above the line are places where 3x + 5 > y.

◦2

Put the graphs of two equations on the same page to see how they interact. For example, the graphs of two linear equations can show you at a glance if the two equations can have the same values -- it depends on whether the lines cross or not. If the lines do cross, it indicates the values that make both equations true at the same time. For example, suppose y = 5x and y = 3x + 20 are both true; graphing these two equations shows instantly that the two lines cross when x = 10 and y = 50. The only time when y = 5x and y = 3x + 20 are both true at the same time is when x = 10 and y = 50.

◦3

Check for roots and extrema of an equation by looking at the graph. Some complex functions have graphs that are not straight lines. These graphs are curves that reach maximum and minimum values. These extrema are easy to see when you have the graph. Other important things like the roots of the equation are also easy to see if you have the graph. The roots are when the curve crosses the x axis. Graphing the equation with a calculator or computer makes finding extrema and roots easy.

Tips & Warnings

•For linear graphs, you only need to consider two points. The points where x = 0 and y = 0 are the easiest to compute.

•Sometimes the points where x = 0 or y = 0 will not exist. These are lines that are parallel to one of the axes and therefore easy to graph

RESOUCES: •EMathLab: Graphing Basics

- Algebra 1 -
**Ms. Sue**, Thursday, October 13, 2011 at 1:31pmhttp://library.thinkquest.org/20991/prealg/graph.html

http://www.wtamu.edu/academic/anns/mps/math/mathlab/beg_algebra/beg_alg_tut21_graph.htm

http://www.purplemath.com/modules/

- Algebra 1 -
**Hello Kitty**, Thursday, October 13, 2011 at 1:32pmThank you Ms. Sue! :-)

- Algebra 1 -
**Ms. Sue**, Thursday, October 13, 2011 at 1:33pmYou're welcome.

- Algebra 1 -
**Hello Kitty**, Thursday, October 13, 2011 at 1:50pmAngel please don't answer my questions.... No offense I just want professional help. :-)

- Algebra 1 -
**JK Pretto**, Sunday, September 1, 2013 at 6:14pmHey Hello Kitty, you should probably be thankful for Angel taking the time and pointing out the question for you, it seems she put a lot of effort on it, be grateful for that.