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Liula [17]
3 years ago
15

Given Sn=2n^2 - 5n, find

Mathematics
1 answer:
brilliants [131]3 years ago
6 0

Answer:

a) -3

b) 117

c) 100

Step-by-step explanation:

(a) 2(1)²-5(1)

1²= 1

2×1= 2

2-5= -3

(b) 2(9)²-5(9)

9²= 81

81×2= 162

162-45= 117

(c) 2(4)²-5(4) +2(8)²-5(4)

4²=16

16×2= 32

32-20= 12

8²=64

64×2= 128

128-40= 88

88+12= 100

hope it helps!

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After visiting the Titanic, Captain Ngoc and Commander Chris are taking the SSN-21 Seawolf submarine back to the surface of the
Dennis_Churaev [7]

Answer:

D(h) = 55h - 2000

1670 m

Step-by-step explanation:

Given :

Starting elevation, D = - 2000 m (2000 m below sea level)

Rate, h = 55 m per hour.

The slope - intercept relation :

y = mx + c

m = slope = rate of change

c = intercept

In the scenario given :

-2000 = intercept

55 = rate of change

D(h) = 55h - 2000

After 6 hours :

D(6) = 55(6) - 2000

D(6) = - 1670 m

5 0
3 years ago
How many terms are in the exspression 4{8+3x]
slava [35]

2 terms

Step-by-step explanation:

4[8+2x]

=4*8+4*2x

=32+8x

therefore there are 2 terms

hope it helps u if yes pls mark brainliest

8 0
3 years ago
Read 2 more answers
A birdhouse has a shadow that is 12
Nadusha1986 [10]
First we need to find the scale factor that 5 has decreased by

5/3=0.6

Then multiply the length of the birdhouse shadow by that scale factor

12*0.6=7.2 feet

So the new birdhouse shadow length is 7.2 feet

Hope this helps!
4 0
4 years ago
The table represents a linear function.
Pavlova-9 [17]
Using two points to find the slope use
y2-y1/x2-x1
i chose points (0,4) and (2,14)
14-4/2-0
10/2
5
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8 0
3 years ago
two friends went to a restaurant and ordered one plain pizza and two sodas. their bill totaled $15.95. later that day, five frie
oksano4ka [1.4K]
X= cost per pizza
y= cost per soda


1ST VISIT TO RESTAURANT
x + 2y= $15.95

2ND VISIT TO RESTAURANT
3x + 5y= $45.90


STEP 1
multiply equation from 1st visit by -3. Will be able to solve by elimination method in step 2.

-3(x + 2y)= -3(15.95)
multiply -3 by each term

(-3 * x) + (-3 * 2y)= (-3 * 15.95)

-3x - 6y= -47.85


STEP 2
add 2nd visit equation to new 1st
visit equation in step 1.

3x + 5y= 45.90
-3x - 6y= -47.85
x term will cancel out; solve for y

-y= -1.95
divide both sides by -1

y= $1.95 per soda


STEP 3
substitute y value in either original equation to solve for x

x + 2y= $15.95

x + (2 * 1.95)= 15.95
multiple in parentheses

x + 3.90= 15.95
subtract 3.90 from both sides

x= $12.05 per pizza


CHECK
3x + 5y= $45.90
3(12.05) + 5(1.95)= 45.90
36.15 + 9.75= 45.90
45.90= 45.90


ANSWER: Each pizza costs $12.05 and each soda costs $1.95.

Hope this helps! :)
4 0
4 years ago
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