Try adding the two and think of it mentally as if you were drinking the amount of cups of water that's what I do when I have questions like these :))
Answer:

Step-by-step explanation:
Differentiating, you get ...
... x·dy +y·dx +dx +dy = 2x·dx +2y·dy
Collecting terms gives ...
... dy(x +1 -2y) = dx(2x -y -1)
... dy/dx = -(2x -y -1)/(2y -x -1)
Answer:
why does this hurt my head so much
Step-by-step explanation:
Answer:
B. 40 percent
Step-by-step explanation:
First take the new price minus the original price
175-125
50
Divide by the original price
50/125
.4
Multiply by 100%
.4 *100% = 40%