Which of the following parabolas opens down?

Which instruments listed below are examples of the classification idiophone?

rjkz [21]

Idiophone means an instrument that will produce a sound when being struck.
so the answer is B.

4 0

3 years ago

Read 2 more answers

12. Jason wants to walk the shortest distance to get

just olya [345]

Answer:

I don't know

Step-by-step explanation:

but I am I sure that I can you please give it a shot if the harbor though I will Unite it to the wind strength and I will Unite it to the next level up and I will

8 0

3 years ago

Read 2 more answers

Solve the compound inequality for x and identify the graph of its solution. x + 7 < 3 or x - 52 -1 O A. Solution: x < -4 o

aleksley [76]

Answer:

D. x < -4 or x ≥ 4

Step-by-step explanation:

You can eliminate choices A and B because the graph and the inequalities do not agree.

__

You can eliminate choice C because the first inequality tells you ...

x < some value

That means the shading will be to the left of an open circle.

This is only shown in Choice D.

_____

<em>Additional comment</em>

You can work multiple choice questions several different ways. I like to choose the simplest, which often means you do not actually need to work the problem. You only need to be able to identify ...

answers that are self-consistent
answers that are consistent with problem requirements
answers that are consistent with numerical and geometric facts

Here, we can eliminate incorrect answers by throwing out those that are not self-consistent and that are not consistent with the problem statement.

__

If we were to solve the inequalities, we would subtract 7 from both sides of the first one:

x +7 < 3

x < -4 . . . . . . subtract 7 from both sides

and we would add 5 to both sides of the second one:

x -5 ≥ -1

x ≥ 4 . . . . . . add 5 to both sides

If you write these inequalities so the symbols point left, you have ...

x < -4 or 4 ≤ x

This tells you shading is "outside" the segment between -4 and 4, and that there is an open-circle at x=-4. This is consistent with the number lines of choices B and D. However, these inequalities are <em>not consistent</em> with what is written in choice B.

6 0

3 years ago

Juan is working two summer jobs, making $12 per hour babysitting and making $16 per hour lifeguarding. In a given week, he can w

Semenov [28]

\text{Let }b=

Let b=

\,\,\text{the number of hours babysitting}

the number of hours babysitting

\text{Let }l=

Let l=

\,\,\text{the number of hours lifeguarding}

the number of hours lifeguarding

\text{\textquotedblleft at most 17 hours"}\rightarrow \text{17 or fewer hours}

“at most 17 hours"→17 or fewer hours

Use a \le≤ symbol

Therefore the total number of hours worked in both jobs, b+lb+l, must be less than or equal to 17:17:

b+l\le 17

b+l≤17

\text{\textquotedblleft at least \$240"}\rightarrow \text{\$240 or more}

“at least $240"→$240 or more

Use a \ge≥ symbol

Juan makes $12 per hour babysitting, so in bb hours he will make 12b12b dollars. Juan makes $16 per hour lifeguarding, so in ll hours he will make 16l16l dollars. The total amount earned 12b+16l12b+16l must be greater than or equal to \$240:$240:

12b+16l\ge 240

12b+16l≥240

\text{Plug in }\color{green}{3}\text{ for }b\text{ and solve each inequality:}

Plug in 3 for b and solve each inequality:

Juan worked 3 hours babysitting

\begin{aligned}b+l\le 17\hspace{10px}\text{and}\hspace{10px}&12b+16l\ge 240 \\ \color{green}{3}+l\le 17\hspace{10px}\text{and}\hspace{10px}&12\left(\color{green}{3}\right)+16l\ge 240 \\ l\le 14\hspace{10px}\text{and}\hspace{10px}&36+16l\ge 240 \\ \hspace{10px}&16l\ge 204 \\ \hspace{10px}&l\ge 12.75 \\ \end{aligned}

b+l≤17and

3+l≤17and

l≤14and

12b+16l≥240

12(3)+16l≥240

36+16l≥240

16l≥204

l≥12.75

\text{The values of }l\text{ that make BOTH inequalities true are:}

The values of l that make BOTH inequalities true are:

\{13,\ 14\}

{13, 14}

\text{(the final answer is this entire list)}

(the final answer is this entire list)

6 0

3 years ago

Please help! If the current in a circuit is 3 + j2 amps and the resistance is 4 - j3 ohms, what is the voltage?

Leona [35]

The value of the voltage is 18 - j volts if the current in a circuit is 3 + j2 amps and the resistance is 4 - j3 ohms option (c) is correct.

<h3>What is a complex number?</h3>

It is defined as the number which can be written as x+iy where x is the real number or real part of the complex number and y is the imaginary part of the complex number and i is the iota which is nothing but a square root of -1.

We have:

The current in a circuit is 3 + j2 amps and the resistance is 4 - j3 ohms.

As we know,

V = IR

V = (3 + j2)(4 - j3)

$\rm V=\left(3\cdot \:4-2\left(-3\right)\right)+\left(3\left(-3\right)+2\cdot \:4\right)j$

j² = -1 (complex part)

After simplification:

V = 18 - j volts

Thus, the value of the voltage is 18 - j volts if the current in a circuit is 3 + j2 amps and the resistance is 4 - j3 ohms option (c) is correct.

Learn more about the complex number here:

brainly.com/question/10251853

#SPJ1

6 0

2 years ago