the rate of change of a linear function is the same slope
the slope of a linear function is the coefficient that accompanies the variable in this case the variable is x and the slope is -2
so, the rate of change for y is -2
To check if two vectors are orthogonal(perpendicular), simply check their dot product, if their dot product is 0, then they're perpendicular, let's check.

to check if two vectors are parallel, simply check their slope by doing a b/a check, if the slopes are the same, then they're indeed parallel to each other, let's check.

well, there you have it, the slopes are the same.
If you would like to write each rate as a unit rate, you can do this using the following steps:
$2 ... 5 cans of a soup
$1 ... x cans of a soup = ?
2 * x = 5 * 1
2 * x = 5
x = 5 / 2
x = 2.5 cans of a soup per $1
$2 ... 5 cans of a soup
$x = ? ... 1 can of a soup
2 * 1 = 5 * x
2 = 5 * x
x = 2 / 5
x = $0.4 per 1 can of a soup
Answer:
30 = 80 %
40= 20 %
Step-by-step explanation
I'm sorry for not writing how to do it but it's something like if 30 = 100 then if we had 40 occupying 20 percent of that acid then we will get 32 percent