graphing equations

[Irma Garcia]

how do u graph a equation that has decimal?
7.1x -3.9y=1.4
how do i graph this?
i dont know how to get started.

[Loren]

Multiply both sides by 10 and go from there.

[mmm4444bot]

Determine the two intercepts; plot them, and use a straightedge to draw a line through them.

The x-intercept is on the x-axis, so the y-coordinate must be zero because we don't go up or down.

(x, 0)

Substitute 0 into the equation for y, and solve for x.

The y-intercept is on the y-axis, so the x-coordinate must be zero because we don't go left or right.

(0, y)

Substitute 0 into the equation for x, and solve for y.

[Irma Garcia]

where did u get the 10 from?

[Irma Garcia]

after i am done with this process do can i get the slope and the x- intercept?
after i substitude the 0 for y i got this...
7.1x-3.9y=1.4
7.1x-3.9(0)=1.4
7.1x=1.4
7.1x/7.1=1.4/7.1
x=197.18 is this correct?

[mmm4444bot]

Did they ask you to do anything other than graph the equation ? I mean, are you free to graph it using any method?

[mmm4444bot]

7.1x/7.1=1.4/7.1

x=197.18 is this correct? No

Are you using a calculator to divide 1.4 by 7.1 ?

[mmm4444bot]

Here is a set of axes for you to use, when you get the coordinates of two points to plot.

The axes go from x = -1 to 1 horizontally and y = -2 to 1.5 vertically.

[attachment=0:35wun6d9]xy-plane.JPG[/attachment:35wun6d9]

[mmm4444bot]

Since both intercepts are close to the Origin, let's plot four points, instead of two. It's easy.

In addition to the two intercepts, also find the following.

(-1, y)

(1, y)

In other words, find y when x = -1 and also when x = 1.

Plotting four points will make it easier to draw a fairly accurate line segment.

[mmm4444bot]

Your work is okay, but you made an arithmetic mistake at the end.

x = 1.4/1.7

x = 0.197

I think we can round that off to 0.2, for graphing purposes.

The x-intercept is (0.2, 0).

What do you get for the y-intercept (0, y) ?