The equation of a parabola is given. y=1/4x^2−3x+18 What are the coordinates of the focus of the parabola?

4. Let the numbers be x - 2, x, and x + 2, where x is an odd number.
2(x² - 4) - 4x = (x + 2)² + 21
2x² - 8 - 4x = x² + 4x + 4 + 21
2x² - 4x - 8 = x² + 4x + 25
x² - 8x - 33 = 0
(x - 11)(x + 3) = 0

x = 11, or -3
When x = 11, x - 2 = 9, x + 2 = 13

When x = -3, x - 2 = -5, x + 2 = -1

Explanation: You are on the right track. However, rather than having three unknown variables, try to reduce your working out to one unknown variable. Since you know they are consecutive odd numbers, you can simply let x be the middle term and the other two be + and - 2, provided x is an odd number.

That will reduce your variable issues, and helps as the first and third provide a difference of two squares, and this works out very nicely.

Q5: is essentially the same process. Let your variables be something in the form of one unknown variable, and you should be okay from there. Let me know if you're stuck.

5 0

3 years ago

The principal P is borrowed at a simple interest rate are for a period of time T. Find the loans future value A, or the total am

Xelga [282]

Answer:

The total amount due after five years is $57,000.

Step-by-step explanation:

Recall that simple interest is given by the formula:

$\displaystyle A=P(1+rt)$

Where A is the final amount, P is the principal amount, r is the rate, and t is the time (in years).

Since we are investing a principal amount of $38,000 at a rate of 10.0% for five years, P = 38000, r = 0.1, and t = 5. Substitute:

$\displaystyle A=38000(1+(0.1)(5))$

Evaluate. Hence:

$\displaystyle A=\$ 57,000$

The total amount due after five years is $57,000.

4 0

3 years ago

What is the value of y in the sequence below? 2,y,18, -54,162,

snow_lady [41]

First, let's check if the sequence is geometric or arithmetric.

If arithmetric, the sequence will have common difference.

Arithmetric

$\displaystyle \large{a_{n + 1} - a_n = d}$

d stands for a common difference. Common Difference means that sequences must have same difference after subtracting.

Geometric

$\displaystyle \large{ \frac{a_{n + 1}}{a_n} = r}$

r stands for a common ratio.

To find the value of y, you can check the sequence. If we try subtracting the sequences, the differences are different. That means the sequences are not arithmetric. That only leaves the geometric sequence.

Let's check by dividing sequences.

We have:

2,y,18,-54,162,...

Let's check by divide -54 by 18 and 162 by -54. We need to divide more than one so we can prove that the sequence is geometric.

$\displaystyle \large{ \frac{ - 54}{18} = - 3 } \\ \displaystyle \large{ \frac{ 162}{ - 54} = - 3}$

Hence, the sequence is geometric.

Because the common ratio is -3. Let these be the following:

$\displaystyle \large{ a_{n + 1} = y } \\ \displaystyle \large{ a_n = 2 } \\ \displaystyle \large{ r = - 3 }$

From the:

$\displaystyle \large{ \frac{a_{n + 1}}{a_n} = r}$

Substitute the values in.

$\displaystyle \large{ \frac{y}{2} = - 3}$

Multiply the whole equation by 2 to isolate y.

$\displaystyle \large{ \frac{y}{2} \times 2 = - 3 \times 2} \\ \displaystyle \large{ y = - 6}$

Therefore, the value of y is -6.

7 0

3 years ago