Four students each made a list a of prime numbers.
2 answers:
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Answer:
Step-by-step explanation:
This is a parabola since a quadratic is a parabola. The standard form for a parabola is y = ax² + bx + c
but before we do that, we will use the vertex form, since it will make our work easier at the beginning.
First and foremost, when we plot the vertex and the given point, the vertex is higher up than is the point; that means that this parabola opens upside down, and its vertex form will be
y=-|a|(x - h)² + k
The absolute value is out in front of the a, so we know that the value of a is positive, but the quadratic itself is negative (upside down) and we will find that math takes care of that negative that needs to be out front. So we need to solve for a by filling in the x, y, h, and k values from the point and the vertex: x = -7, y = 0, h = -3, k = 4
0 = a(-7 - (-3))² + 4 and
0 = a(-7 + 3)² + 4 and
0 = a(-4)² + 4 and
0 = a(16) + 4 and
0 = 16a + 4 and
-4 = 16a so
Now that we know a, we can plug it back into the vertex form and then put it into standard form from there.
Now we will FOIL out what's inside the parenthesis to get
Simplify by distributing the -1/4 into the parenthesis:
Combine like terms to get
And there you go!
Answer:
Cost of a snack size bag of chips = $0.8
Cost of a water bottle = $1.6
Cost of a gallon of milk = $3.4
Step-by-step explanation:
Let the cost of water bottle = $a
Cost of 1 gallon milk = $b
and cost of 1 bag of chips = $c
So, cost of 4 gallons of milk, 6 bottles of water and 5 bags of chips = $(4b + 6a + 5c)
4b + 6a + 5c = 27.2 -----(1)
Cost of one water bottle = 2 × cost of one bag of chips
a = 2c -----(2)
A gallon of milk = cost of water bottle + $1.80
b = a + 1.8
From equation (2)
b = 2c + 1.8 -----(3)
Now we substitute these values from equations (2) and (3) in equation (1)
4(2c + 1.8) + 6(2c) + 5c = 27.2
8c + 7.2 + 12c + 5c = 27.2
25c = 27.2 - 7.2
c =
c = $0.8
From equation (2)
a = 2×0.8
a = $1.6
From equation (3)
b = 2(0.8) + 1.8
b = 1.6 + 1.8
b = $3.4
Therefore, cost of a snack size bag of chips = $0.8
Cost of a water bottle = $1.6
Cost of a gallon of milk = $3.4