She multiplied it by 5, because that would make the equation:
2.5 + y = 125
So when we add -y and y cancel out
Answer:
x = 90
y = 60
Step-by-step explanation:
Let x = student
Let y = non-student
x + y = 150
4x + 8y = 840 <—— Use elimination/addition ethos for both equations
8 (x + y = 150)
-1 (4x + 8y = 840) <—— Let’s eliminate y
8x + 8y = 1200
+ -4x - 8y = -840
—————————————
4x = 360
x = 90
x + y = 150 <— substitute for x from above
90 + y = 150
- 90 = - 90 <— subtract from both sides
y = 60
The answer to your problem is C
For it to be non-linear, the rate of change cannot be constant. For the first table the rate is a constant 1 and the second table has a constant rate of -1. The 3rd and 4th tables have no constant rate and thus are non-linear.
The 4th table is increasing while the 3rd table is decreasing.
So the 3rd table, Set C, is the only non-linear negative association between x and y.