Question

Need help.

Answer 1

Number 8

Answer 2

What went wrong when you worked on this?

Answer 3

Desmos won't graph the last one.

Answer 4

Could you separate the last line into two lines on Desmos?

Answer 5

Should I do that?

Answer 6

Look at the first 2 inequalities. Temporarily drop the inequality symbols. Graph the resulting equations. Determine their point of intersection. Graph thise two lines in the 1st quadrant of a system of coordinate axes.

Answer 7

Shade the area UNDER these two lines, in the 1st quadrant only.

Use the Draw utility, below.

Answer 8

Totally confused.

Answer 9

Well, I suppose it's confusing to get different advice from different people. First of all, how much experience do you have in graphing straight lines?

Answer 10

The line x + y = 5 could be re-written as y=-x+5. slope is -1 and y-intercept is 5.
Can you graph this line?

Answer 11

Need your involvement. If confused, ask questions to clarify whatever is confusing you.

Answer 12

Desmos, while useful, is not going to be available to you at test time. So why depend upon it? Also, the scale divisions on the Desmos graph are inappropriate; the largest value either x or y can have is 8. Not 100, 200, 300.

Why not sketch the line x+y=5 in the Draw utility?

Answer 13

Drawing it on paper.

Answer 14

Fine, but unless you can take a photo of your drawing and share the image with me, the image on paper will be of use mainly to you, not to me.
Describe what you have drawn. What does it look like? What are the x- and y-intercepts?

Answer 15

I can scan it to my computer.

Answer 16

Fine, but you might find it MUCH faster to sketch your graphs in the Draw utility.

Answer 17

I can't draw.

Answer 18

I'm sorry. You do need to have some kind of rough sketch to show what's happening here. Please jump in, get your feet wet and learn something from the experience.

Answer 19

My vertices are as follows:
(0,0)
(5,0)
(2,3)
(0,4)

Answer 20

Good enuf. Can you now find the coordinates of the four "corner points?"

Where the vertical line intersects the graph of x+y=5, you get y=???

Answer 21

I then plug those vertices into the equation, correct?

Answer 22

All right. We'll use your four vertices. Take one at a time. Take the x-coordinate and the y-coordinate and subs. them into P=4x+y.

Which of the four points gives you the largest value for P?

Answer 23

Give me a second, gonna work it out on paper.

Answer 24

ok

Answer 25

Your method is completely correct, it seems. So I'm not actually calculating P for each vertex. You can do that and have reasonable faith in your own results.

Answer 26

@mathmale