#HELP ME WITH 2 MATH ASSIGNMENTS MY FINAL ARE GONNA HURT IF I DONT DO IT! THEY ARE IN A WEEK!!

58 messages · Page 1 of 1 (latest)

storm arch
hazy harnessBOT
pale lodge
# storm arch

This algebra YouTube video tutorial explains how to graph systems of linear inequalities in two variables. It contains plenty of examples and practice problems that will help you to master the topic.

Linear Inequalities: https://www.video-tutor.net/inequalities.html

â–¶ Play video
storm arch
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DOESNT HELP

storm arch
timber snow
storm arch
timber snow
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If they're willing

storm arch
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handins are due monday

timber snow
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In qn 5

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@storm arch

storm arch
timber snow
storm arch
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ok

timber snow
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So we're trying to graph the inequality for -2x+1>5

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Firstly let's draw the line y=-2x+1 on the axes

storm arch
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yes

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so

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we need are x and y

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y= -2(0)+1

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so x is 0 and 1 is y?

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???

timber snow
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Man

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Do you not know how to sketch a line?

storm arch
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YES I SUCK AT GRAPHING

timber snow
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Take each square to be one unit

storm arch
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yeah

timber snow
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Alright so

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The y intercept of this line is 1

storm arch
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yes

timber snow
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And since the gradient of this line is -2,for every one step we move to the right

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We move 2 units down

timber snow
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So these two points

storm arch
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yes

timber snow
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Alright so draw the line

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Actually nvm mb

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I think I mightve misread the question 😭

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Since -2x+1>5

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Then -2x>4
So x<-2

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So all you really have to do is draw a semi solid line x=-2

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Then shade the region to the left

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Mb😭

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@storm arch

storm arch
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oh

loud epoch
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@Kit, Q4 is asking you for:

$\big{(x,,y):-2x+1>5,\ x\in\mathbb{R},\ y\in\mathbb{R}\big}$

Do you understand what all that notation means?

frigid windBOT
loud epoch
#

It means that you need to find all points with

coordinates $(x,,y)$, where both $x$ and $y$ are

real numbers, subject to the restriction that

$-2x+1>5$.

In other words, whatever the $x$ coordinate is,

when it is multiplied by $-2$ and then 1 is added,

the result must be bigger than 5.

So, trying $x = 4$, for example, gives

$-2x+1=-2\times 4 + 1 = -7$ and since $-7 > 5$

is NOT true, you can't have any point with $x= 4$.

Trying, $x = -4$, as another example, gives

$-2x+1=-2\times -4 + 1 = 8 + 1 = 9$ and since

$9 > 5$ IS true, you can have points with $x= -4$.

Now, which points with $x=-4$? Well, we have no

restrictions on $y$ apart from it being real, so any

point $(-4,, y)$ will be a member of the set we seek.

This should get you a long way to finding all the

solutions, noting that you need to find all possible

$x$-values by solving the inequation $-2x + 1 > 5$.

Does this make any sense?

frigid windBOT
loud epoch
# timber snow Yea my bad

It's all good, everyone makes mistakes, and you did reflect on what you had said and catch it 🙂

loud epoch
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@Kit, Q2, in the second image, covers material you also

need for Q5.

In Q2, you are given the sketch already showing a

boundary, which is a straight line. If we assume that

that line is the boundary of the region we seek to find,

we need only test a point that is NOT on the line.

For example, test the origin, $(0,,0)$, in which case:

$\text{LHS}\ = 4y + 8x = 4(0) + 8(0) = 0 + 0 = 0$

$\text{RHS}\ = 2$

So, the statement $\text{LHS}\ \le\ \text{RHS}$ is the same as $0 \le 2$,

and so is TRUE. Thus, $(0,,0)$ is in the desired region,

and we would shade on that side of the boundary.

Unfortunately, looking closely, the line drawn is strange.

For the region $4y +8x \le 2$, the boundary will be the

equality case, with equation $4y + 8x = 2$, or $2y + 4x = 1$.

This line has intercepts at $\left(0,, \frac{1}{2}\right)$ and at $\left(\frac{1}{4},,0\right)$,

and has a gradient of $m = -2$.

The line shown in the diagram has intercepts at $(0,,2)$ and

$(1,,0)$, and a gradient of $m=-2$... and so is parallel to

the actual boundary, but above it.

FYI, the line shown on the diagram is the boundary line

of the region $4y + 2x \le 8$.

frigid windBOT
storm arch