You would need to make them eliminate so I would multiply the entire first one by 2.5 to make the X's cancel out. So you would end up with -5X+7.5Y=17.5. The X's would cancel and you would be left with 15.5Y=15.5. So Y=1. Then replace Y into one of the equations. I'm going to use the top again. -2X+3(1)=7. Subtract 3 from both sides to get -2x=4. Divide both sides by negative 2 to get X=-2. So the solution would be (-2,1)
As shown in the figure, we have two straight line. One of them has a negative slope and the other has a positive one. In two dimensions, the equation for non-vertical lines is often given in the slope-intercept form by:

being m the slope of the line and <span>b the y-intercept of it.
On the other hand, if x = 0 then y = b.
First of all we will order the equations above without </span>inequalities<span> like this:
A. </span>

,

<span>
B. </span>

,
C. 
,
D. 
,

<span>
As shown in the figure b = -1 for one straight and b = 4 for the second one. This values take place when x = 0. So, we discard C and D, because if x = 0, then:
</span>
For C, b = 1 and b = 4
For D, b = -1 and b = -4
Let's analyze A and B. So:
For A, m = 5 and m = 3
For B, m = 5 and m = -3
Therefore, we discard A because of the statement above.
Finally the answer is B. So, the inequalities are:
(1)

(2)

Let's prove this answer. We will take the point (2, 0) that is in the region in gray. So, substituting this point in the inequalities, we have:
(1)

(2)

In fact, this is true.
Answer:
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Step-by-step explanation:
Given

Required
Determine 
We know that:

This gives:


Collect like terms


Take square roots


By tan identity


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Answer: it will take the faster computer 15 minutes to do the job on its own.
Step-by-step explanation:
Let t represent the number of minutes it will take the faster computer to do the job on its own. It means that the rate at which it does the job per minute is 1/t
If it takes the slower computer 30 minutes to do the job on its own. It means that the rate at which it does the job on its own per minute is 1/30
By working together, they would work simultaneously and their individual rates are additive. Working together it takes two computers 10 minutes to send out a company's email. It means that the rate at which both computers work together per minute is 1/10 Therefore,
1/t + 1/30 = 1/10
Cross multiplying by 30x, it becomes
3x = x + 30
3x - x = 30
2x = 30
x = 30/2
x = 15 minutes
okey
you needed the sum or division?