if the telephone was invented in 1876 how old was it in 1991 how long had it been around

The value of x that makes sense for the expression is the domain of the expression

[tex]\sqrt{-2x^2}[/tex]

For the above expression to have a defined value, the expression in the bracket must be positive.

However, x^2 will always be positive, and -2 will ensure that the expression is always negative, except when x = 0

Hence, the value of x makes sense for [tex]\sqrt{-2x^2}[/tex] is 0

[tex]\sqrt{(-2x)^3}[/tex]

For the above expression to have a defined value, the expression in the square root must be positive.

However, the power of 3 will ensure that the expression is always positive only when x is less than or equal to 0

Hence, the value of x must not exceed 0 for [tex]\sqrt{(-2x)^3}[/tex] to make sense

Read more about domain at:

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Answer: First answer = x<=0 and second answer is x<0

Step-by-step explanation: The other guy got the work correct but the answer wrong. The real answer is x≤0 for -2x^2 and the second answer is x < 0.

Answer:

-11/14.

Step-by-step explanation:

Slope =(y2-y1)/ (x2 - x1)

Here y2 = 7 and y1 = -4, x2 = -7 and x1 = 7.

So slope

= (7 - (-4)/ -7-7)

= -11/14.

Answer: C

Step-by-step explanation: x represents the number of classes, not the cost of classes.

Answer:

true

Step-by-step explanation:

i learned this in like 7th grade

Answer:

Option B is correct.

add 4 times the second equation to 3 times the first equation

Step-by-step explanation:

Answer:

B) add 4 times the second equation to 3 times the first equation

Step-by-step explanation:

So you have these two equations:

2x - 4y = 6

-3x + 3y = 12

In order "to solve this system of equations by elimination" we want to make BOTH of the equations have a term (in this case the y term) and have the same coefficient (that's the number right next to the y) If they are the exactly same number, even the same sign in front, then we would subtract the equations. If they have the same coefficient but different signs, then we would add the equations. This will eliminate the y term completely. So in order to make them have the same coefficient. We'll multiply the first equation by 3 and the second equation by 4

3(2x - 4y = 6)

4(-3x + 3y = 12) multiplying all the way across the equation (distributing)

We'll get

6x -12y = 18

-12x + 12y = 48 Then you are actually adding from the top, down and get one equation from adding the two existing ones together.

-6x = 66 And then you are able to solve it by dividing both sides by -6 to get

x = -11

You can then use either equation and x = -11 to find y. Your solution is the x, y pair. You can check it by putting the x and y into both equations and finding it makes a true statement in both.

Answer:

[tex]x=0.3090984+\frac{2\pi n}{3},0.73809914+\frac{2\pi n}{3}[/tex]

Step-by-step explanation:

[tex]5sin(3x)-1=3[/tex]

[tex]5sin(3x)=4[/tex]

[tex]sin(3x)=\frac{4}{5}[/tex]

[tex]3x=0.92729521+2\pi n,2.21429743+2\pi n[/tex]

[tex]x=0.3090984+\frac{2\pi n}{3},0.73809914+\frac{2\pi n}{3}[/tex]

Answer:

See explanation

Step-by-step explanation:

Dilation of 4

G (0, 1) G' (0, 4)

F (1, 1) F' (4, 4)

Gx'/Gx = 0 / 0 = 0

Gy' / Gy = 4 / 1 = 4

Fx' / Fx = 4 / 1 = 4

Fy' / Fy = 4 / 1 = 4

Answer:

Variable = 4 (1/4x) 1/Variable - 12 - 12

(Hope this helps.)

The Distributive Property shows that 6(p + q) is equivalent to 6p + 6q

The distributive property tells us how to solve expressions in the form of a(b + c).  The distributive property is sometimes called the distributive law of multiplication and division. It is given by:

a(b + c) = ab + ac

Given the expression:

6(p + q)

Using the distributive property:

= 6p + 6q

Find out more on distributive property at: https://brainly.com/question/2807928

Answer:

x=33 and y=36

Step-by-step explanation:

You can rewrite the equation into

x+2=4/3x-9

Now you can subtract 2 on both sides

x=4/3x-11

Now subtract 4/3x on both sides:

-1/3x=-11

Multiply -3 on both sides:

x=33

Now substitute x with 33

y=33+3

y=36

Thus x=33 and y=36

Hope this helps!

Answer:

60

Step-by-step explanation:

Since the angles A, D, and G are congruent then sum of given angles is eaqual to 180 degrees

x + 20 + 2x + x  = 180 add like terms

4x + 20 = 180 subtract 20 from both sides

4x = 160 divide both sides by 4

x = 40

Angles B, E, and H are congruent so E is also  = x + 20 and x = 40 so angle E = 60

Answer:

55

55x11 = 55

(Meeting character limit)

Answer:

I believe it would be 605$

Step-by-step explanation:

1 2 3 4 5

wa

Answer:

124°

Step-by-step explanation:

180°( n - 2 )

180° ( 5 - 2 ) = 540°

( 2x - 3 )° + ( 3x - 2 )° + 2( 3x - 4 )° + ( 2x + 7 )° = 540°

( 2x + 3x + 6x + 2x ) + ( - 3 - 2 - 8 + 7 ) = 540

13x - 6 = 540

13x = 546

x = 42

3(42) - 2 = 124°

Answer:

Multiply each coordinate point by 1.5, y=1.5x

Step-by-step explanation:

Answer:

1/2

Step-by-step explanation:

We know two points on the line

(-1,1) and (3,3)

The slope of a line is given by

m = (y2-y1)/ (x2-x1)

   = ( 3-1)/(3- -1)

    = (3-1) /(3+1)

    = ( 2/4

   = 1/2

Step-by-step explanation:

the slope is the ratio of "y coordinate difference / x coordinate difference".

so, let's find 2 good points (I mean by that with integer coordinates). I see e.g.

(-1, -1) and (0, -7)

x changes by +1 (from -1 to 0).

y changes by -6 (from -1 to -7).

so, the slope is -6/1 = -6.

D is the right answer.

Answer:

Step-by-step explanation:

36 inches  = 3 ft

max height of lumber stack is 7 - 3 = 4 ft.

4 ft = 48 inches

48 inch / 1.5 inch/board = 32 boards

Answer:

Ramona spent 110 minutes on homework

Step-by-step explanation:

You want to add up all the minutes spent on homework altogether.

20 +20 = 40

40 + 40 = 80

80 + 30 = 110

110 + 0 = 110

So, Ramona spent a total of 110 minutes on homework. Hope this helps!

Answer:

2/11

Reasoning, there are 36 possible (and equally likely) combinations that we can obtain from two dice. Of these 11 (1,5 2,5 3,5 4,5 5,5 6,5 5,6 5,4 5,3 5,2 5,1) would allow us to ‘know’ that “one dice (not necessarily the first) has shown a 5”. Of these 11 possibilities only two also contain a 4. So the probability is 2/11

Step-by-step explanation: have a good day

Answer

First one is A

Second one is B

Third one is D

Problem 1

Answer: Choice A

(30, 225); Rocket reaches max height of 225 ft after 30 seconds.

-------------------

Explanation:

Distribute the 0.25 through to get

y = 0.25(60x-x^2)

y = 15x - 0.25x^2

y = -0.25x^2 + 15x

This is in standard form y = ax^2+bx+c with a = -0.25, b = 15 and c = 0.

The first two values mentioned lead to this x coordinate of the vertex.

h = -b/(2a)

h = -15/(2*(-0.25))

h = -15/(-0.5)

h = 30

This tells us the answer is between A and C.

If you were to plug x = 30 into the original equation, you'll get y = 225. It means that after x = 30 seconds, the rocket has reached its max height of 225 feet. Therefore, the answer must be choice A.

===========================================================

Problem 2

Answer:  Choice B

(x-3)^2 = -8(y-6)

-------------------

Explanation:

vertex = base of the bulb = (3,6)

focus = top of the bulb = (3,4)

This flashlight is pointed downward, which forms a downward opening parabola.

The distance from the vertex to the focus is p = 2 units. This is known as the focal distance.

We'll plug that in along with the vertex (h,k) = (3,6) in the formula below

4p(y-k) = (x-h)^2

4*2(y-6) = (x-3)^2

8(y-6) = (x-3)^2

Unfortunately that equation above produces a parabola that opens upward. To fix things, we stick a negative out front on either side, which will reflect the parabola over the x axis to make the parabola open downward. That leads us to choice B.

===========================================================

Problem 3

Answer:  D) square

-------------------

Explanation:

We can form a point by intersecting the plane through the point where the two cones meet. The plane needs to be parallel to the base of each cone.

We can also form a line. To do so, we intersect the plane at exactly  along the edge of the cone. Make the plane tangent to the cone.

Lastly, we can form a circle by intersecting any plane parallel to the cone's base. This plane cannot pass through the meeting point of the two cones. Rather, the plane passes through one of the cones.

Those three previous paragraphs mean that we can rule out choices A,B,C. The only thing we can't form is a square. We can form straight lines, but we cannot form perpendicular lines needed to get a square. Nice work on selecting the correct answer.

Answer:

-5+

Step-by-step explanation:

Slope of the line passing through the points (1, 4) and (3, 2) is -1.

The slope of the line is the ratio of the rise to the run, or rise divided by the run. It describes the steepness of line in the coordinate plane.

The slope intercept form of a line is y=mx+b, where m is slope and b is the y intercept.

The slope of line passing through two points (x₁, y₁) and (x₂, y₂) is

m=y₂-y₁/x₂-x₁

The line passing through the points (1, 4) and (3, 2)

Plug in the points in the slope formula.

Slope = 2-4/3-1

=-2/2

=-1

Hence, slope of the line passing through the points (1, 4) and (3, 2) is -1.

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Answer:

d. 7, -14, 28, -56, 112

Step-by-step explanation:

f(2) = -2(7) = -14

f(3) = -2(-14) = 28

f(4) = -2(28) = -56

f(5) = -2(-56) = 112

Answer:

The answer is 4

Step-by-step explanation:

(-2.4)(10) / -3(2)

-24/-6

=4

Answer:

The answer will be 4! Hope this helps