Can somebody help me with this. Will mark brainliest.

bearhunter [10]

First question: 2x = 50
Explanation:
“2 times as many” in this situation means that the pages justin read (50) is twice as Colin’s. Meaning that to find the number of pages Colin’s read, we will have to divide 50 by 2.
2x = 50 is an equivalent representation of that.

2nd question:
(Choose these correct statements):
• 9h represents how much money Sofia earns babysitting for h hours.
• Sofia babysat for 3 hours.
• If Sofia babysits for 5 hours, she will earn $45

Have a nice day (brainliest please)

6 0

3 years ago

A rocket is fired with an initial vertical velocity of 40 m/s from a launch pad 45 m high, and its height is given by the formul

N76 [4]

Answer:

1) 125 meters

2) For 9 seconds.

Step-by-step explanation:

The rocket's height is given by the formula $-5t^2+40t+45$ .

Notice that this is a quadratic.

Part 1)

Since this is a quadratic, the highest height the rocket goes will be the vertex of our quadratic. Remember that the vertex of a quadratic in standard form is:

$(-\frac{b}{2a}, f(-\frac{b}{2a}))$

So, let's identify our coefficients. The standard quadratic form is:

$ax^2+bx+c$

Therefore, in this case, our a is -5, b is 40, and c is 45.

So, let's find the x-coordinate of our vertex. Substitute 40 for b and -5 for a. This yields:

$x=\frac{-(40)}{2(-5)}$

Multiply and reduce. So:

$x=-40/-10=4$

Now, substitute 4 for t to find the height. So:

$-5(4)^2+40(4)+45$

Evaluate:

$=-5(16)+40(4)+45$

Multiply and add:

$=-80+160+45=125\text{ meters}$

Therefore, the highest the rocket goes up is 125 meters.

Part 2)

To find out for how much time the rocket is in the air, we can think about after how many seconds after launch will the rocket land.

If the rocket lands, the height h will be 0. So, we can set our expression equal to 0 and solve for t:

$-5t^2+40t+45=0$

First, let's divide everything by -5. This yields:

$t^2-8t-9=0$

We can factor:

$(t+1)(t-9)=0$

Zero Product Property:

$t+1=0\text{ or } t-9=0$

Solve for t:

$t=-1\text{ or } t=9$

In this case, since t is our time in seconds, -1 seconds does not make sense. So, we can remove -1 from our solution set.

Therefore, 9 seconds after launch, the rocket will touch the ground.

Therefore, the rocket was in the air for 9 seconds.

And we're done!

6 0

3 years ago

Find the value of x. 60o 79o 70o 47o

LekaFEV [45]

180-2(55)-x=0
180-110-x=0
70-x=0
-x=-70
x=70°

3 0

3 years ago

Juan got on an elevator at the middle floor of a building, went up 4 floors, down 3 floors, up one floor, down 9 floors, where h

xenn [34]

There are 14 floors in the building, because since Juan went up 4 floors, down 3 floors, and up one floor; so we know that he is 2 floors above from where he originally started. Once he went down 9 floors he passed the starting point and went to the bottom of the building. So, the middle must have been the 7th floor. Once I knew that I multiplied 7*2 and it got me 14. So in total there are 14 floors. I hope this helped ^^

5 0

3 years ago

Look at ΔABC and its 90° rotation. If AB is 8 inches long, what is the length of A'B' ?

chubhunter [2.5K]

Because the triangle is only rotated, AB and A'B' would be equal. 8 in.

3 0

3 years ago

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