Please help me with this geometry/algebra

[Ignore the 2 problems] I need help on #9

Lena [83]

Comment.
9A
Let's use (a) as an example. What number is in front of the x inside be brackets? If I gave you the choice of 1,2,3,4,5 which number is it out of those 5?

If you chose 5, you have the second best answer. You are reading outside the brackets. Not what we need.

If you choose 1, you are well on your way. There is a 1 beside the x.

Now go to the outside of the brackets. What's in front of the x? 1,2,3,4,5.. There is only one number you can choose. It's a 5. So the result outside the brackets is 5x. How did 1x become 5x? You had to put a 5 on the blank to the left of the brackets..

5(5 + x) = 5x + ___ What goes on the line to the right of 5x? Rule whatever you do to one side of a plus sign inside the brackets, you must do to the other side of the plus sign.

It becomes 5*5

So the blank is filled with 25. And here's the answer.
5(5 + x) = 5x + 25 <<<< answer..
Stop don't do anything more. 5x and 25 are not like terms. They don't mix

9B
Let's make this one brief so that you have something to do. What did you multiply 5 by to get 10? You should answer 2.
2(x + 5) = ___ x + 10

What you do on one side of the plus sign, you must do on the other. So what's in front of the x on the right?

2(x + 5) = 2x + 10 <<<< answer

5 0

3 years ago

Solve the inequality.

DedPeter [7]

C>12
Y=-3 -3+13= 10
7x-14 Multiply
112

3 0

3 years ago

What is the Numerical coefficient of 13hk?

Rufina [12.5K]

Answer:

13

Step-by-step explanation:

A numerical coefficient is a number placed before an unknown value to indicate the quantity of the unknown value.

5 0

3 years ago

Suppose that a wall is constructed from concrete blocks where a block is a normal random variable with mean 11 kg and standard d

Artemon [7]

Answer:

The value for k is about k = 11.093kg.

Step-by-step explanation:

To answer this question, that is, P(x<k) = 0.85, we can use the standardized value for a raw score, or the formula for obtaining z-scores:

$\\ z = \frac{x - \mu}{\sigma}$ [1]

Where

$\\ x$ is the raw score.

$\\ \mu$ is the population mean.

$\\ \sigma$ is the population standard deviation.

In this case, we are asking to find a value x = k, so that 85% of the blocks have weights less than k (kg).

We have also to use the values for the cumulative standard normal distribution with $\\ \mu = 0$ and $\\ \sigma = 1$ to find the value of z that corresponds to a probability of 0.85.

First step: find the z that corresponds to the probability of 0.85.

To use the formula [1], as we previously mentioned, we first need to find the value of z that corresponds to a probability of 0.85 using the cumulative standard normal distribution table (available in any Statistics books or on the Internet). Then, for a cumulative probability of 0.85, the corresponding value for z = 1.03 (approximately).

Second step: solve the formula [1] for x.

Solving this formula for x, we have:

$\\ z = 1.03$

$\\ \mu = 11kg$

$\\ \sigma = 0.09kg$

Then (without units):

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

$\\ 1.03 = \frac{x - 11}{0.09}$

$\\ 1.03*0.09 = x - 11$

$\\ (1.03*0.09) + 11 = x$

So

$\\ x = (1.03*0.09) + 11$

$\\ x = 0.0927 + 11$

$\\ x = 11.0927 \approx 11.093 = k$

Thus, this value for x = 11.093 equals the value for k (x = k) so that

$\\ P(x$

Then

$\\ P(x$ or

$\\ P(x$

We can see the graph below showing this value of k = 11.093kg for which 85% of the blocks have weights less that it (x = k = 11.093kg).

4 0

3 years ago

For the function f(x) = x2 -12, find (f o f-1)(4) A. 0 B. 4 C. 10 D. 6

slega [8]

We actually don't need to do any computation. By definition, the inverse function $f^{-1}$ changes the role of input and output. So, if a function f maps x onto y, the inverse function maps y onto x.

You have to think like this: if the function makes a step further, the inverse function makes that same step back.

This means that the composition $f \circ f^{-1}$ is always the identity function $f(x) = x$ . In fact,

$(f\circ f^{-1})(x) = f(f^{-1}(x)) = x$

So, for every function, you have

$(f\circ f^{-1})(4) = f(f^{-1}(4)) = 4$

5 0

3 years ago