Help with graphing an equation...test tomorrow!

[Gr8fu13]

Ofcourse my 12 year old daughter decides to wait til last minute to ask for help with this one and I know this is where I came for help when I had problems in math so I told her I would post her question and she would have to check back in on it after awhile to see if anyone had answered her. Anyway, here it is:

-4x + 3y > 3000 needs to be graphed.

What was done so far is:

-4x + 3y > 3000
+4x +4x

3y > 3000 + 4x
3 3 3

y > 1000 + 4x
3

So, would 1000 be one of your points on the graph?

Also:

-4x + 3y > 3000
-3y -3y

4x > 3000 - 3y
4 4 4

y > 750 - 3y
4

So would 750 be another point on the graph?

Thanks in advance for any help you can offer...

 

[renegade05]

Ofcourse my 12 year old daughter decides to wait til last minute to ask for help with this one and I know this is where I came for help when I had problems in math so I told her I would post her question and she would have to check back in on it after awhile to see if anyone had answered her. Anyway, here it is:

-4x + 3y > 3000 needs to be graphed.

What was done so far is:

-4x + 3y > 3000
+4x +4x

3y > 3000 + 4x
3 3 3

y > 1000 + 4x
3

So, would 1000 be one of your points on the graph?

Also:

-4x + 3y > 3000
-3y -3y

4x > 3000 - 3y
4 4 4

y > 750 - 3y
4

So would 750 be another point on the graph?

Thanks in advance for any help you can offer...

Well a point on this graph would be represented by 2 coordinates. eg: (0,1000)

Are you sure that is suppose to be the inequality symbol?

This describes the region above and including the line \(\displaystyle y=1000+\frac{4}{3}x\).

 

[mmm4444bot]

-4x + 3y > 3000 needs to be graphed.

Like renegade says, the graph is a shaded region of the xy-plane.

-4x + 3y > 3000
+4x+4x

3y > 3000 + 4x
3 3 3

y > 1000 + 4x
3

So, would 1000 be one of your points on the graph?

That work is correct.

The y-intercept of the line is 1,000 units above the origin.

The slope of the line is 4/3.

"Greater than or equal to" means that all of the points on the line are included in the graph, as well as all of the points in the xy-plane above the line.

We show this by drawing a solid line and shading above it. (If the symbol were "greater than" instead, then the graph would not contain the line itself, and we would show that by drawing a dotted line.)

Also:

-4x + 3y > 3000
-3y -3y

4x > 3000 - 3y
4 4 4

No, the first way is much better because linear equations solved for y show us the slope and y-intercept. That makes it easier to graph the line.

 

[Gr8fu13]

My mom said the same thing. She thought it would be an equal sign there too. My teacher drew this one on the board and we copied it down. This is what she ment it to look like...:-?

 

[Gr8fu13]

I got up early to check if there were any replies before I had to get ready for school. Thanks so much for the help mmm444!! So I had it right, I just did not have to do the second part...