Answer:
Either one: the two line have a point in common, or infinite: they are the same line.
Answer:

Step-by-step explanation:
The equation of a quadratic function in vertex form is given by:

Where (h,k) is the vertex.
It was given in the question that the vertex of the parabola is (-1,4).
When we substitute the vertex into the formula we get:

The parabola also passes through (4,19) hence it must satisfy its equation.



We divide both sides by 25 to get:

Hence the quadratic function is:

Answer:
Step-by-step explanation:
Amount of water in tank 1 = amount of water in tank 2
30t +25 = -20t + 1000
Add 20t to both sides
30t + 20t + 25 = -20t + 20t + 1000
50t + 25 = 1000
Subtract 25 from both sides
50t + 25 - 25 = 1000 - 25
50t = 975
Divide both sides by 50
t = 975/50 = 39/2

t = 19 minutes 30 seconds
After 19 1/2 minutes both tanks will have 610 liters of water