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velikii [3]
2 years ago
14

Expand (3x+7)(3x-7) =

Mathematics
2 answers:
saveliy_v [14]2 years ago
8 0

Answer:

9 {x}^{2}  - 49

Step-by-step explanation:

Do FOIL, first outside inside last

3x × 3x = 9x^2

3x × -7 = -21x

7 × 3x = 21x

7 × -7 = -49

9 {x}^{2}   - 21x + 21x - 49 \: midde \: cancels \: each \: other \: out

So it would just be 9x^2 - 49

Tamiku [17]2 years ago
8 0

(3x + 7)(3x - 7) =

= 9x² + 21x - 21x - 49

= 9x² - 49

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3 years ago
Find the sum of the first four terms of the geometric sequence shown below. 4​, 4/ 3​, 4/9​, ...
user100 [1]
It's evident that the first four terms are 4, 4/3, 4/9, and 4/27. So the fourth partial sum of the series is

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It's as easy as adding up the fractions, but I bet this is supposed to be an exercise in taking advantage of the fact that the series is geometric and use the well-known formula for computing such a sum.

Multiply the sum by 1/3 and you have

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Now subtracting this from S_4 gives

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3 0
3 years ago
Given that BC = 7, AB = 17.89, and C is between A and B, what is the length of ?
ivanzaharov [21]
*assuming that ABC is a straight line** 
<span>then you have </span>
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8 0
3 years ago
Read 2 more answers
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Answer:

y = 1.25

Step-by-step explanation:

Use the direct variation equation y = kx, and solve for k:

y = kx

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So, the equation is y = -0.25x. Solve for y when x = -5

y = -0.25x

y = -0.25(-5)

y = 1.25

So, y = 1.25 when x = -5

8 0
2 years ago
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Fynjy0 [20]

Answer:

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Step-by-step explanation:

it is equivalent to 12:24 because 12/2= 6 and 24/2 = 12 so 6:12 is your answer!

4 0
3 years ago
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