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2 years ago

If a = -3, find the value of a) 2a b) a^2 c) 3a^2

Mathematics

2 answers:

White raven [17]2 years ago

8 0

Answer:

a) -6

b) 9

c) 27

Step-by-step explanation:

$2( - 3) = - 6 \\ { - 3}^{2} = - 9 \\ 3 {( - 3)}^{2} = 27$

Virty [35]2 years ago

3 0

$\textbf{a)}\\\\2a=2(-3) = -6\\\\\textbf{b)}\\\\a^2 = (-3)^2 = 9\\\\\textbf{c)}\\\\3a^2 = 3(-3)^2 = 3 \cdot 9 = 27$

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Wittaler [7]

3. Credit Card: (1842.66 - 250) (.145/12) = $19.24

Savings: 250(0.04/12) = $0.83

Difference = 19.24 - 0.83 = $18.41

4. Credit Card: (1842.66 - 500) (.145/12) = $16.22

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3 years ago

Read 2 more answers

6. Two observers, 7220 feet apart, observe a balloonist flying overhead between them. Their measures of the

MaRussiya [10]

Answer:

The ballonist is at a height of 3579.91 ft above the ground at 3:30pm.

Step-by-step explanation:

Let's call:

h the height of the ballonist above the ground,

a the distance between the two observers,

$a_1$ the horizontal distance between the first observer and the ballonist

$a_2$ the horizontal distance between the second observer and the ballonist

$\alpha _1$ and $\alpha _2$ the angles of elevation meassured by each observer

S the area of the triangle formed with the observers and the ballonist

So, the area of a triangle is the length of its base times its height.

$S=a*h$ (equation 1)

but we can divide the triangle in two right triangles using the height line. So the total area will be equal to the addition of each individual area.

$S=S_1+S_2$ (equation 2)

$S_1=a_1*h$

But we can write $S_1$ in terms of $\alpha _1$ , like this:

$\tan(\alpha _1)=\frac{h}{a_1} \\a_1=\frac{h}{\tan(\alpha _1)} \\S_1=\frac{h^{2} }{\tan(\alpha _1)}$

And for $S_2$ will be the same:

$S_2=\frac{h^{2} }{\tan(\alpha _2)}$

Replacing in the equation 2:

$S=\frac{h^{2} }{\tan(\alpha _1)}+\frac{h^{2} }{\tan(\alpha _2)}\\S=h^{2}*(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})$

And replacing in the equation 1:

$h^{2}*(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})=a*h\\h=\frac{a}{(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})}$

So, we can replace all the known data in the last equation:

$h=\frac{a}{(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})}\\h=\frac{7220 ft}{(\frac{1 }{\tan(35.6)}+\frac{1}{\tan(58.2)})}\\h=3579,91 ft$

Then, the ballonist is at a height of 3579.91 ft above the ground at 3:30pm.

6 0

3 years ago

Each pair of points lies on a line with the given slope. Find x.

Gwar [14]

Answer:

the answer is -2 inorder to get -1 slope

8 0

3 years ago

There are 135 people in a sport centre. 77 people use the gym. 62 people use the swimming pool. 65 people use the track. 27 peop

umka21 [38]

Answer:

The correct answer is $\frac{2}{9}$ .

Step-by-step explanation:

There are 135 people in a sport centre.

Let the experiment be to pick a person from the sport centre who only uses exactly one of the facilities.

Total number of possible outcomes = 135

For the gym:

77 people use the gym.

27 people use the gym and the pool.

31 people use the gym and the track.

4 people use all three facilities.

Total number of people using only the gym are 77 - ( 27 + 31 + 4) = 15

For the swimming pool:

62 people use the swimming pool.

27 people use the gym and the pool.

23 people use the pool and the track.

4 people use all three facilities.

Total number of people using only the swimming pool are 62 - ( 27 + 23 + 4) = 8

For the tracks:

65 people use the track.

23 people use the pool and the track.

31 people use the gym and the track.

4 people use all three facilities.

Total number of people using only the tracks are 65 - ( 23 + 31 + 4) = 7

A person is selected at random.

Favorable outcomes = 7 + 8 + 15 = 30

Probability that the person uses exactly one of the facilities = $\frac{Favorable}{Total}$ = $\frac{30}{135} = \frac{2}{9}$ .

5 0

3 years ago

Estimate the value of this expression by rounding each number to the nearest whole unit. (1.74)(9.95)(3.46) A. 80 B. 54 C. 60 D.

Vlada [557]

The answer is C. 60 because if you multiply 1.74*9.95*3.46 you will get 59.90298 and if you round to the nearest whole then it's 60

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4 years ago