We are given : Zeros x=7 and x=4 and leading coefficent 1.
In order to find the quadratic function in standard form, we need to find the factors of quadratic function first and the multiply by given leading coefficent.
For the given zeros x=7 and x=4, we get the factors (x-7) and (x-4).
So, we need to multiply (x-7) and (x-4) by foil method.
We get
(x-7)(x-4) = x*x + x* -4 -7*x -7*-4
x^2 -4x -7x +28.
Combining like terms, we get
-4x-7x = -11x
x^2 -4x -7x +28 = x^2 -11x +28.
Now, we need to multiply x^2 -11x +28 quadratic by leading coefficent 1.
We get
1(x^2 -11x +28) = x^2 -11x +28.
Therefore, the required quadratic function in standard form is x^2 -11x +28.
The main idea here is to "translate" the words into maths.
First we need to identify the unknowns and label these.
We need to know the number if dimes and the number of quarters. So lets say
x: number of dimes
y: number of quarters
Now lets write equations from the written problem.
We know that there are 36 coind total, thus:
x + y = 36
We also know that the coins total 5.85 dollars, but it is better to count in cents, that is 585 cents.
x are the number of dimes, their value is x*10
y are quarters with value of y*25
thus:
10x+25y=585
We have two equations and two unknowns now, that needs to be solved to get the answer.
x + y = 36
10x+25y=585
First you need to multiply 36 *$30.22=$1087.92
This gives you the total amount paid
Then subtract 1087.92-900=187.92
This gives you the amount of money you paid in finance charges.
