Answer:
is the correct answer.
Step-by-step explanation:
We know that vertex equation of a parabola is given as:
where is the vertex of the parabola and
are the coordinate of points on parabola.
As per the question statement:
The parabola opens upwards that means coefficient of is positive.
Let
Minimum of parabola is at x = 3.
The vertex is at the minimum point of a parabola that opens upwards.
Putting value of a and h in the equation:
Formula used:
Comparing the equation formulated above with the options given we can observe that the equation formulated above is most similar to option A.
Comparing and
13 = 9+k
k = 4
Please refer to the graph attached.
Hence, correct option is
If we have 420 books for every 7 shelves and are looking for how many books are on 4 shelves, we need to set up fractional proportions.
We have 7 shelves for every 420 books, so we will have our first fraction like this:
7/420.
We also have 4 shelves for every x books, so our second fraction will be 4/x.
Set these fractions up as an equation.
7/420 = 4/x
To solve for x, we need to cross multiply the numerators of one fraction with the denominators of the other fraction.
In other words, multiply the top number of one fraction by the bottom number of the other question.
It should look like this:
7(x)
420(4)
7(x) = 7x
420(4) = 1680
Set your products up as an equation.
7x = 1680
Now to solve for x, we need to simplify.
Currently, x is being multiplied by 7.
To get x alone, divide 7x by 7.
Remember, what you do to one side of an equation, you must do to the other, so divide 1680 by 7.
7x / 7 = x
1680 / 7 = 240
You are left with:
x = 240.
For every 4 shelves you have 240 books.
I hope this helps!