Question

HELP! Algebra I Question! PLEASE, FAN MEDAL TESTIMONIAL!!!

Answer 1

The graph below shows the solution to a system of inequalities.

Solid line joining ordered pairs 0, 3.75 and 15, 0. Shade the portion of the graph above the line in the first and second quadrant

Which of the following inequalities is modeled by the graph?

5x + 4y ≥ 15; y ≥ 0

5x - 4y ≥ 15; y ≥ 0

5x + 4y ≤ 15; y ≥ 0

-5x - 4y ≥ 15; y ≥ 0

Answer 2

You need to determine the slope of the graph first.

Answer 3

Well, the slope is negative...The y-intercept is like 3. something and the x-intercept is 15...

Answer 4

If you figure the slope of the line then you can figure the line formula.
Slope = \[\frac{ y-y1 }{ x-x1 }\]

Answer 5

Oh I think I remember this.

Answer 6

Um, I just take two random points?

Answer 7

No, you're given two actual points and are to find the equation of a line through them. Remember what to do?

Answer 8

I guess not. Ha ha. I know I have to input the values of course.

Answer 9

Your are given the points above (0,.375) and (15,0)

Answer 10

It actually said 4, btw. But anyways...\[\frac{ 4-0 }{ 0-15 }=\frac{ 4 }{ -15 }=-0.26666666666\]

Answer 11

So now that I have slope, now what?

Answer 12

Here's what to do:
1) find the slope of the line through these 2 points;
2) insert this slope and the coordinates of either one of the given points into the point-slope form of the equation of a line: y-y0 = m (x-x0).
What part of this can you do yourself and what part requires some guidance?

4? Where did that come from?

Answer 13

Wait, what? I think I already did Part 1...

Answer 14

-3.75/15 is the slope..not -0.26666

Answer 15

Yes, except for an arithmetic error. Are you willing to accept Nelson's calculation of the slope?

Answer 16

I reduced Nelson's -3.75/15 and obtained the simple proper fraction -1/4.

So, DG, are we in agreement or no? Be certain that you're comfortable with the slope calculation as well as the result.

Answer 17

Oh, okay. Yes, I am comfortable.

Answer 18

So, your slope is m=-1/4. Please choose one of the points (which one you choose does not matter at all).

Answer 19

Now please do Part 2 of my 2-part instructions, above.

Answer 20

Okay...so let me start with a.

\[5x+4y \ge15\]\[5(-15) + 4(-0.375)\ge15\]\[-75+4(-0.375)\ge15\]\[-75+-1.5\ge15\]\[-76.5\ge15\]
So A is the answer, right?!

Answer 21

Oops, fail. It isn't.

Answer 22

At first glance it is! If you pick a point from within the shaded area and substitute its coordinates into the inequality, and the inequality is true, Right.
I'm so glad that you checked for yourself and found this not to be true.

think: what will you do next?

Answer 23

It's C. I solved B and it wasnt true then I solvedC and it was true.

Answer 24

Are you completely satisfied with this solution, or have you further questions?

Answer 25

I actually have four more questions! But I must make another post so your and/or my computer won't lag and so you can get full credit.

Answer 26

Oh, if it only were that easy to ensure our computers won't crash! I've lost about 90 minutes today because of failed Internet connections.
Please post the most challenging of the several problems you have left. I'll help you with one. Then, I need to quit for the day.

Answer 27

Okay!