Answer:
a
Step-by-step explanation:
the equation for a circle centered at orgin is x^2+y^2=r where r is the radius. multiplying, adding, or subtracting any numbers to the x and y components such as the other choices here causes the circle to be translated about the graph.
Set it up like a regular equation. I used:

As you can see, however, I inserted the "less than" symbol rather than the equal sign because values greater than a certain value can also equal "x". Solve it like a normal equation and you will arrive at:
<u>
</u>

This means that, as long as x is greater than 45, "6x" will be greater than "3x+135". Thus, if you bring 46 students, the Science Center will cost less.
Answer:
Troposphere
Step-by-step explanation:
We humans live in the troposphere, and nearly all weather occurs in this lowest layer. Most clouds appear here, mainly because 99% of the water vapor in the atmosphere is found in the troposphere.