3 years ago

A train covers 168 miles at a speed of 42 mph. How much time dod it take?

Mathematics

1 answer:

Sergio039 [100]3 years ago

3 0

Answer:

4 hours

Step-by-step explanation:

42x?=168

?=4

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If a = pi +3j - 7k, b = pi - pj +4k and the angle between a and is acute then the possible values for p are given by

PIT_PIT [208]

Answer:

The family of possible values for $p$ are:

$(-\infty, -4) \,\cup \,(7, +\infty)$

Step-by-step explanation:

By Linear Algebra, we can calculate the angle by definition of dot product:

$\cos \theta = \frac{\vec a\,\bullet\,\vec b}{\|\vec a\|\cdot \|\vec b\|}$ (1)

Where:

$\theta$ - Angle between vectors, in sexagesimal degrees.

$\|\vec a\|, \|\vec b \|$ - Norms of vectors $\vec {a}$ and $\vec{b}$

If $\theta$ is acute, then the cosine function is bounded between 0 a 1 and if we know that $\vec {a} = (p, 3, -7)$ and $\vec {b} = (p, -p, 4)$ , then the possible values for $p$ are:

Minimum ( $\cos \theta = 0$ )

$\frac{p^{2}-3\cdot p -28}{\sqrt{p^{2}+58}\cdot \sqrt{2\cdot p^{2}+16}} > 0$

Maximum ( $\cos \theta = 1$ )

$\frac{p^{2}-3\cdot p -28}{\sqrt{p^{2}+58}\cdot \sqrt{2\cdot p^{2}+16}} < 1$

With the help of a graphing tool we get the family of possible values for $p$ are:

$(-\infty, -4) \,\cup \,(7, +\infty)$

7 0

3 years ago

For what value of the constant c does the above equation have x = 2 as the only solution?

Stolb23 [73]

The answer is A, -41.
Substitution:
-8(2) - (-41)
-16 + 41
25.
Square root of 25 = 5.
5 = 4x - 3.
5 = 4(2) - 3
5 = 8 - 3
5 = 5.

8 0

3 years ago

Divide the numbers above

Iteru [2.4K]

Answer:

hjhkhhuh

Step-by-step explanation:

vnhju

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3 years ago

Let f(x) = x2 + x + 2 and g(x) = 2x2 + 5. Find f(g(x)). Show each step of your work

pochemuha

Answer:

idk hbu

Step-by-step explanation:

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3 years ago

PLZZ help with this!!!!

murzikaleks [220]

Answer:

2x² + 15x + 27

Step-by-step explanation:

(2x + 9)(x+3)

2x² + 6x + 9x+ 27

2x² + 15x + 27

6 0

3 years ago

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