*Macmillan Science Library: Mathematics*. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.

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## Graphs of Straight Lines

The graph of the simple equation *y* = 1*x*, or *y = x*, is graphed in (a) below. The line passes through every coordinate point where *x = y*, such as (2, 2) or (–3, –3).

Notice what happens to the graph of the equation when the parameters of the equation are changed by using a different coefficient for x, such as *y* = 3*x*. As part (a) shows, the new line has a steeper slope. If the coefficient is further increased, the slope will become even steeper, and the line will become closer to vertical.

Conversely, if the coefficient for *x* is decreased, a different change in the line occurs. As part (b) above shows, the line for has a more gradual slope than the line for *y=x*. If the coefficient were to be further decreased, the line would become flatter, and it would...

This section contains 1,054 words(approx. 4 pages at 300 words per page) |