Answer:
B
Step-by-step explanation:
x + y =6
x - y = 4
A. 3+3=6, but 3-3 doesn't equal 4
B. 5+1=6 and 5-1 equals 4
C. 6+0 equals 6 but 6-0 doesn't equal 4
D. 2+4 equals 6 but 2-4 doesn't equal 4
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.
The slope of this line is -1/6.
2 Point: (6,2) (-6,6)
x₁ y₁ x₂ y₂
Remember:
rise change in y y₂ - y₁ 6 - 2 4
---------- = ------------------- = ------------- = ----------- = ----------
run change in x x₂ - x₁ -6 - 6 -12
Simplify 4/-12
4 ÷ 4 1
------- = ------------- = -1/3
-12 ÷ 4 -3
The slope of the line is -1/3.
In the order of operation, multiplying or dividing don't take preference over the other. So with them, you work from left to right.
This means for this question, you first divide, then multiply.