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2 years ago

Is the statement true or false? 4-2(3+7 =4 - 2 • 3 + 2 • 7

Mathematics

1 answer:

Vesnalui [34]2 years ago

6 0

False, 4-2(3+7) = -16 and 4-2•3+2•7= 12

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The graph h = −16t^2 + 25t + 5 models the height and time of a ball that was thrown off of a building where h is the height in f

Thepotemich [5.8K]

Answer:

part 1) 0.78 seconds

part 2) 1.74 seconds

Step-by-step explanation:

step 1

At about what time did the ball reach the maximum?

Let

h ----> the height of a ball in feet

t ---> the time in seconds

we have

$h(t)=-16t^{2}+25t+5$

This is a vertical parabola open downward (the leading coefficient is negative)

The vertex represent a maximum

The x-coordinate of the vertex represent the time when the ball reach the maximum

Find the vertex

Convert the equation in vertex form

Factor -16

$h(t)=-16(t^{2}-\frac{25}{16}t)+5$

Complete the square

$h(t)=-16(t^{2}-\frac{25}{16}t+\frac{625}{1,024})+5+\frac{625}{64}$

$h(t)=-16(t^{2}-\frac{25}{16}t+\frac{625}{1,024})+\frac{945}{64}\\h(t)=-16(t^{2}-\frac{25}{16}t+\frac{625}{1,024})+\frac{945}{64}$

Rewrite as perfect squares

$h(t)=-16(t-\frac{25}{32})^{2}+\frac{945}{64}$

The vertex is the point $(\frac{25}{32},\frac{945}{64})$

therefore

The time when the ball reach the maximum is 25/32 sec or 0.78 sec

step 2

At about what time did the ball reach the minimum?

we know that

The ball reach the minimum when the the ball reach the ground (h=0)

For h=0

$0=-16(t-\frac{25}{32})^{2}+\frac{945}{64}$

$16(t-\frac{25}{32})^{2}=\frac{945}{64}$

$(t-\frac{25}{32})^{2}=\frac{945}{1,024}$

square root both sides

$(t-\frac{25}{32})=\pm\frac{\sqrt{945}}{32}$

$t=\pm\frac{\sqrt{945}}{32}+\frac{25}{32}$

the positive value is

$t=\frac{\sqrt{945}}{32}+\frac{25}{32}=1.74\ sec$

8 0

2 years ago

Consider the numbers 4/15 and 3/10 (a) Compare the numbers. (B) find a fraction between the two given numbers

valentinak56 [21]

As a decimal 4/15 = 0.2666667
As a decimal 3/10 = 0.3 [talk about close]
3/10 is bigger.

You could take an average to find something between 4/15 and 3/10
1/2(4/15 + 2/10)
1/2(8/30 + 6/30)
1/2(14/30)
1/2(7/15)
7/30 is between the two given numbers..

5 0

2 years ago

3 times the square root of 18

AnnyKZ [126]

Answer:

9 square root of 2 or 12.73

7 0

2 years ago

The speed of light is 186,182 miles per second. How many miles can light travel in a non-leap year? Express your answer in scien

zepelin [54]

So theres 366 days in a leap year,
you need to find hours, minutes, and then seconds
366 x 24 = 8,784 hours
8,784 x 60 = 527,040 minutes
527,040 x 60 = 31,622,400 seconds
31,622,400 seconds x 186,182 mps = 5.88 x 10^10
therefore light travels 5.88 x 10^10 in one leap year

7 0

2 years ago

Please help me this will mark brainiest thx I will appreciate it thank you

Savatey [412]

Answer:

z=40 degrees

x=90 degrees

y=40 degrees

Step-by-step explanation:

To solve z you know that 50+90+z= 180 degrees. So z equals 40. To solve x you subtract 90 from 180 to get 90 degrees. To solve you add 50+x+y. You know that x= 90. You would add the angles together to get 180 degrees. 50+90=140 and 180-140 equals 40. Sorry if i'm wrong.

6 0

2 years ago