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2 years ago

Which expression is equivalent to (3x2-6) – (5x2 - 7x+5)-(9x + 3)?

Mathematics

1 answer:

andrezito [222]2 years ago

4 0

Answer:

It equals -2

Step-by-step explanation:

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The position function for a free-falling object is s(t) = -16t^2 + vt +5. A ball is thrown upward from the top of a 400-foot bui

mixer [17]

Answer:

6.21 seconds

Step-by-step explanation:

The position function of a free-falling object is,

$s(t) = -16t^2+v_0t+s_0$

Where,

$s_0$ = initial height of the object,

$v_0$ = initial velocity of the object,

Here,

$s_0=400\text{ feet}$

$v_0=35\text{ feet per sec}$

Hence, the height of the ball after t seconds,

$s(t)=-16t^2+35t+400$

When s(t) = 0,

$\implies -16t^2+35t+400=0$

$t=\frac{-35\pm \sqrt{35^2-4\times -16\times 400}}{2\times -16}$

$t=\frac{-35\pm \sqrt{1225+25600}}{-32}$

$\implies t\approx -4.02\text{ or }t\approx 6.21$

∵ Time cannot be negative,

Hence, after 6.21 seconds the ball will reach the ground.

4 0

2 years ago

9.4 The heights of a random sample of 50 college stu- dents showed a mean of 174.5 centimeters and a stan- dard deviation of 6.9

gladu [14]

Answer: a) (176.76,172.24), b) 0.976.

Step-by-step explanation:

Since we have given that

Mean height = 174.5 cm

Standard deviation = 6.9 cm

n = 50

we need to find the 98% confidence interval.

So, z = 2.326

(a) Construct a 98% confidence interval for the mean height of all college students.

$x\pm z\times \dfrac{\sigma}{\sqrt{n}}\\\\=(174.5\pm 2.326\times \dfrac{6.9}{\sqrt{50}})\\\\=(174.5+2.26,174.5-2.26)\\\\=(176.76,172.24)$

(b) What can we assert with 98% confidence about the possible size of our error if we estimate the mean height of all college students to be 174.5 centime- ters?

Error would be

$\dfrac{\sigma}{\sqrt{n}}\\\\=\dfrac{6.9}{\sqrt{50}}\\\\=0.976$

Hence, a) (176.76,172.24), b) 0.976.

8 0

2 years ago

Andrew has one book that is two and 378 inches thick and a second book that is 3.56 inches thick if he stacks the books about ho

Georgia [21]

2.378 + 3.56 = 5.938

two and 378 inches = 2.378

8 0

2 years ago

I need to transpose the following equation to find the term (g)<br><br> V^2=2gh

nataly862011 [7]

$v^2=2gh\\\\2gh=v^2\ \ \ \ |divide\ both\ sides\ by\ 2h\\\\\boxed{g=\frac{v^2}{2h}}$

7 0

2 years ago

Read 2 more answers

The area of the shaded region is 20 cm. Find the value of x

dolphi86 [110]

If you could put more info ab this then i would understand what u want me to put

3 0

2 years ago