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3 years ago

Evaluate 3x^2- 9 when x=-2

Mathematics

2 answers:

murzikaleks [220]3 years ago

6 0

Answer:

Step-by-step explanation:

We know x = -2, so we can substitute -2 in for x

3x^2- 9

3*-2^2-9

Solve the exponent first (PEMDAS)

3*4-9

Multiply next

12-9

Subtract

FrozenT [24]3 years ago

3 0

Answer:

Step-by-step explanation:

3x^2- 9 =

= 3(-2)² - 9

= 3×4 - 9

= 12 - 9

= 3

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Infinite over E n=1 4(0.5)^n-1

yan [13]

Answer:

S = 8

Step-by-step explanation:

An infinite geometric series is defined as limit of partial sum of geometric sequences. Therefore, to find the infinite sum, we have to find the partial sum first then input limit approaches infinity.

However, fortunately, the infinite geometric series has already set up for you. It’s got the formula for itself which is:

$\displaystyle \large{\lim_{n\to \infty} S_n = \dfrac{a_1}{1-r}}$

We can also write in summation notation rather S-term as:

$\displaystyle \large{\sum_{n=1}^\infty a_1r^{n-1} = \dfrac{a_1}{1-r}}$

Keep in mind that these only work for when |r| < 1 or else it will diverge.

Also, how fortunately, the given summation fits the formula pattern so we do not have to do anything but simply apply the formula in.

$\displaystyle \large{\sum_{n=1}^\infty 4(0.5)^{n-1} = \dfrac{4}{1-0.5}}\\\\\displaystyle \large{\sum_{n=1}^\infty 4(0.5)^{n-1} = \dfrac{4}{0.5}}\\\\\displaystyle \large{\sum_{n=1}^\infty 4(0.5)^{n-1} = 8}$

Therefore, the sum will converge to 8.

Please let me know if you have any questions!

6 0

2 years ago

Solve the system of equations 7x+10y=36 y=2x+9

Damm [24]

Answer:

x = -2

y = 5

Step-by-step explanation:

Given two equations

1. 7x + 10y = 36

2. y = 2x + 9

Substitute 2x + 9 for y in equation 1.

We have

7x + 10y = 36

7x + 10(2x + 9) = 36

Distribute 10 into (2x + 9)

We have

7x + 10 x 2x + 10 x 9 = 36

7x + 20x + 90 = 36

27x + 90 = 36

Subtract 90 from both sides to eliminate 90 on the left side

27x + 90 - 90 = 36 - 90

27x = -54

Divide both sides by 27 to isolate x

27x/27 = -54/27

x = -2

Now substitute -2 into either equation to get y

Using equation 2, we have

y = 2x + 9

= 2 x -2 + 9

= -4 + 9

= 5

x = -2

y = 5

Check

7(-2) + 10(5) = 36

5 0

3 years ago

ruby is visiting San Francisco. From her hotel she walks 1 block west ans 4 blocks south to a coffee shop. Then she walks 5 bloc

Deffense [45]

The museum is 4 blocks east and 10 blocks south

7 0

3 years ago

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cricket20 [7]

-8/100 or back 8 yards

6 0

3 years ago

HELPPP. DO TODAY SO PLEASE HELP!!!!!!!!!!

oksian1 [2.3K]

Answer:

47/6cm or $7\frac{5}{6}$ cm

Step-by-step explanation:

FE= $2\frac{2}{3}$

FA= 5/12

AB= 2/3

CD=2

ED= $1\frac{1}{4}$

BC= 5/6

All=47/6 or $7\frac{5}{6}$

6 0

2 years ago