Answer:
all work is shown and pictured
Answer:

Step-by-step explanation:

Step-by-step explanation:
If x is the volume of the first tank, and y is the volume of the second tank, then:
x + y = 55
x = 2y + 4
Solve the system of equations using either substitution or elimination. Using substitution:
2y + 4 + y = 55
3y + 4 = 55
3y = 51
y = 17
Solve for x using either equation.
x + 17 = 55
x = 38
The first tank holds 38 gallons, and the second tank holds 17 gallons.
Answer:

Step-by-step explanation:
For
, we have two cases:

Therefore, for
, we have the following cases:

Solving, we have:
.
Therefore,

Yes it is a function because there are not any repeating x values ( first number in each set of parentheses)