### App Description

Understanding linear equations (equations with an x term and a constant) can be daunting but this program simplifies understanding. Both from an educational standpoint where the student needs to understand coefficients and intercepts or from an engineering standpoint where the user needs to understand the relationship slope and distance this program solves equations in a user friendly environment. Both a help file and glossary of terms have been included to simplify understanding. The equation of a line takes the form of “Y = mX + b “ where the the slope = m and a constant = b. Intercepts exist where the curve crosses or intersects the X and the Y. In the conventional sense one sets the slope and the Y intercept “b” solving the “Y” value for any value of X showing the equation. If the user prefers to solve the equation using just the X and Y intercepts, the “Solve For:” button allows the problem to be setup using the intercepts and solving for “slope” Using the adjustor controls or retro keyboard the equation is displayed automatically. A graph shows the actual curve and the user can manually change the scale to achieve the desired view. If the curve does not intersect the X axis the slope m = 0 and a constant line is displayed. This is all very confusing at first but this program helps to simplify by using adjuster inputs to see how changing the values affect the result and a graph of the actual curve or line. The equation changes as user inputs change along with the graphical output. Help and glossary screens are also provided to further help in understanding quadratic equations. When you are done simply Email the results to your home computer for further analysis. This program is a must for Students and Engineers. It makes the complex understandable. Simply the best linear equation program.Features:

- Updates as You Edit

- Number Pad Digital Entry

- Solve for intercepts or slope

- Calculates Y = mx + b

-Graphs the actual curve to visually relate the equation.

-Help Screen, Glossary and Email

Example: We start with the equation Y = 10 X -11. Select the "Intercept" button and the linear expression is setup that allows you to adjust each of two coefficients "m" and "b" to create the linear equation. Note that there are adjustor buttons to increase or decrease each coefficient. You can as easily use the built-in keyboard by touching the input field. So we have Y = 10.0 X -11. Look at the line calculated from this equation and displayed below in the graph portion of the screen. The program calculates the X and Y intercepts (where the line crosses each axis) and displays them on the right. Note that the graph changes as you adjust the coefficients. If you need to zoom into an area the scaling can be set to manual and the adjustors or keyboard allow changing the graph limits.

Try changing the Solve for Button to Slope. Then use the adjuster buttons to change the X and Y intercepts. Note how the screen displays the graph of the equation and that it intersects the X and Y axis at two different places. If the graph does not intersect the X axis then m = 0 and the line runs parallel to the X axis. See the Glossary screen for any terms that are unclear.

As with all complicated programs this program should be used for reference and learning and the user assumes responsibility for verification, use and application.

Look for other Ray Tools app’s including Quadratic, exponential and logarithmic equations.

This app was developed by Raymond Seymour, after working at General Electric for 37 years he’s now making Engineering apps for iOS. As an inventor he has over 60 granted U.S. Patents.

### App Changes

**January 03, 2013**Initial Release