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Answer:
The given point A (6,13) lies on the equation. True
The given point B(21,33) lies on the equation. True
The given point C (99, 137) lies on the equation. True
Step-by-step explanation:
Here, the given equation is : 
Now,check the given equation for the given points.
1) A (6,13)
Substitute x = 6 in the given equation

⇒ y= 13
Hence, the given point A (6,13) lies on the equation.
2) B (21,33)
Substitute x = 21 in the given equation

⇒ y = 33
Hence, the given point B(21,33) lies on the equation.
3) C (99, 137)
Substitute x = 99 in the given equation

⇒ y = 137
Hence, the given point C (99, 137) lies on the equation.
The line crosses the x-axis at (0,4). The slope is also -1.
Answer:
vertex = (- 7, - 87)
Step-by-step explanation:
given a parabola in standard form : ax² + bx + c : a ≠ 0
Then the x- coordinate of the vertex is
= - 
p² + 14p - 38 is in standard form
with a = 1, b = 14, c = - 38, hence
= -
= -7
substitute x = - 7 into the equation for corresponding value of y
y = (- 7)² + 14(- 7) - 38 = 49 - 98 - 38 - - 87
vertex = (- 7, - 87)
Answer: 
Step-by-step explanation:
It is important to remember that, by definition, proportional relationships have the following form:

Where "k" is the constant of proportionality.
We know that Maddy assume that the relation between the volume and the weight is proportional.
Then, let be "V" the volume in liters and "w" the weight in kilograms.
We can write the following equation:
So, if the boat of 555 liters weights 7.5 kilograms, we can find "k":

In order to solve the exercise, substitute the value of "k" and
into the equation and solve for "w". Then: