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3 years ago

If f(x) = 5x^2 - 7x + 9 and g(x) = 3x^2 - 6x -4, what is (f-g)(x)?

Mathematics

1 answer:

Anastasy [175]3 years ago

7 0

Answer:

(f-g)(x) = 2x^2-x +5

Step-by-step explanation:

i think this is right the question is a little confusing

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The system of equations may have a unique solution, an infinite number of solutions, or no solution. Use matrices to find the ge

Leno4ka [110]

Answer:

Infinite number of solutions.

Step-by-step explanation:

We are given system of equations

$5x+4y+5z=-1$

$x+y+2z=1$

$2x+y-z=-3$

Firs we find determinant of system of equations

Let a matrix A= $\left[\begin{array}{ccc}5&4&5\\1&1&2\\2&1&-1\end{array}\right]$ and B= $\left[\begin{array}{ccc}-1\\1\\-3\end{array}\right]$

$\mid A\mid=\begin{vmatrix}5&4&5\\1&1&2\\2&1&-1\end{vmatrix}$

$\mid A\mid=5(-1-2)-4(-1-4)+5(1-2)=-15+20-5=0$

Determinant of given system of equation is zero therefore, the general solution of system of equation is many solution or no solution.

We are finding rank of matrix

Apply $R_1\rightarrow R_1-4R_2$ and $R_3\rightarrow R_3-2R_2$

$\left[\begin{array}{ccc}1&0&1\\1&1&2\\0&-1&-3\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\1\\-5\end{array}\right]$

Apply $R_2\rightarrow R_2-R_1$

$\left[\begin{array}{ccc}1&0&1\\0&1&1\\0&-1&-3\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\6\\-5\end{array}\right]$

Apply $R_3\rightarrow R_3+R_2$

$\left[\begin{array}{ccc}1&0&1\\0&1&1\\0&0&-2\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\6\\1\end{array}\right]$

Apply $R_3\rightarrow- \frac{1}{2}$ and $R_2\rightarrow R_2-R_3$

$\left[\begin{array}{ccc}1&0&1\\0&1&0\\0&0&1\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]$

Apply $R_1\rightarrow R_1-R_3$

$\left[\begin{array}{ccc}1&0&0\\0&1&0\\0&0&1\end{array}\right]$ : $\left[\begin{array}{ccc}-\frac{9}{2}\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]$

Rank of matrix A and B are equal.Therefore, matrix A has infinite number of solutions.

Therefore, rank of matrix is equal to rank of B.

4 0

3 years ago

How many quarts of pure antifreeze must be added to 8 quarts of a 40% antifreeze solution to obtain a 60% antifreeze solution

anyanavicka [17]

Let q be the number of quarts of pure antifreeze that needs to be added to get the desired solution.

8 quarts of 40% solution contains 0.40 × 8 = 3.2 quarts of antifreeze.

The new solution would have a total volume of 8 + q quarts, and it would contain a total amount of 3.2 + q quarts of antifreeze. You want to end up with a concentration of 60% antifreeze, which means

(3.2 + q) / (8 + q) = 0.60

Solve for q :

3.2 + q = 0.60 (8 + q)

3.2 + q = 4.8 + 0.6q

0.4q = 1.6

q = 4

4 0

2 years ago

Consumer products are required by law to contain at least as much as the amount printed on the package. For example, a bag of po

Troyanec [42]

Answer:

The average bag weight must be used to achieve at least 99 percent of the bags having 10 or more ounces in the bag=9.802

Step-by-step explanation:

We are given that

Standard deviation, $\sigma=0.2$ ounces

We have to find the average bag weight must be used to achieve at least 99 percent of the bags having 10 or more ounces in the bag.

$P(x\geq 10)=0.99$

Assume the bag weight distribution is bell-shaped

Therefore,

$P(\frac{x-\mu}{\sigma}\geq 10)=0.99$

We know that

$z=\frac{x-\mu}{\sigma}$

Using the value of z

Now,

$\frac{10-\mu}{0.2}=0.99$

$10-\mu=0.99\times 0.2$

$\mu=10-0.99\times 0.2$

$\mu=9.802$

Hence, the average bag weight must be used to achieve at least 99 percent of the bags having 10 or more ounces in the bag=9.802

5 0

3 years ago

A bag has more green balls than blue balls, and there is at least one blue ball. Let b represent the number of blue balls and le

Lera25 [3.4K]

Answer:

You must show us the statements that are given. This question can not be answered without that information. Have a nice day!!! :-)

Step-by-step explanation:

5 0

3 years ago

The random variable x has the following probability distribution: x f(x) 0 .25 1 .20 2 .15 3 .30 4 .10 a. Is this probability di

Reptile [31]

Answer and Explanation:

Given : The random variable x has the following probability distribution.

To find :

a. Is this probability distribution valid? Explain and list the requirements for a valid probability distribution.

b. Calculate the expected value of x.

c. Calculate the variance of x.

d. Calculate the standard deviation of x.

Solution :

First we create the table as per requirements,

x P(x) xP(x) x² x²P(x)

0 0.25 0 0 0

1 0.20 0.20 1 0.20

2 0.15 0.3 4 0.6

3 0.30 0.9 9 2.7

4 0.10 0.4 16 1.6

∑P(x)=1 ∑xP(x)=1.8 ∑x²P(x)=5.1

a) To determine that table shows a probability distribution we add up all five probabilities if the sum is 1 then it is a valid distribution.

$\sum P(X)=0.25+0.20+0.15+0.30+0.10$

$\sum P(X)=1$

Yes it is a probability distribution.

b) The expected value of x is defined as

$E(x)=\sum xP(x)=1.8$

c) The variance of x is defined as

$V=\sum x^2P(x)-(\sum xP(x))^2\\V=5.1-(1.8)^2\\V=5.1-3.24\\V=1.86$

d) The standard deviation of x is defined as

$\sigma=\sqrt{V}$

$\sigma=\sqrt{1.86}$

$\sigma=1.136$

5 0

3 years ago