Answer:
<h2> (-1,1)</h2>
Step-by-step explanation:
Given system is

If we graph, the solution would be the interception point between these two lines, because each linear equation represents a line. The lines are attached.
In the graph, you can observe that the solution is the point (-1,1), that is x = -1 and y = 1.
Now, if we want to solve this system by another method, we can just sum both equations and solve for <em>x</em>


Then, we replace this value in one equation to find the other value

Therefore, the solution is (-1,1)
It doesnt say how many she buys at the coin show so we dont know but its going to be more than 6
Answer:
56 meters.
Step-by-step explanation:
Please find the attachment.
Let the leaning tower's be h meters tall, when it was originally built.
We can see from our attachment that the side with length 55.86 meters is hypotenuse and h is adjacent side for 4 degree angle.
Since we know that cosine relates the adjacent and hypotenuse of a right triangle.

Upon substituting our given values we will get,



Therefore, the leaning tower was approximately 56 meters, when it was originally built.
Answer:
negative
Step-by-step explanation:
The graph falls to both the left and right, so the leading coefficient has to be negative, and it must be raised to an even power.
Answer:
The amount of oil was decreasing at 69300 barrels, yearly
Step-by-step explanation:
Given


Required
At what rate did oil decrease when 600000 barrels remain
To do this, we make use of the following notations
t = Time
A = Amount left in the well
So:

Where k represents the constant of proportionality

Multiply both sides by dt/A


Integrate both sides


Make A, the subject

i.e. At initial
So, we have:






Substitute
in 

To solve for k;

i.e.

So:

Divide both sides by 1000000

Take natural logarithm (ln) of both sides


Solve for k



Recall that:

Where
= Rate
So, when

The rate is:


<em>Hence, the amount of oil was decreasing at 69300 barrels, yearly</em>