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r-ruslan [8.4K]
3 years ago
9

Suppose y varies directly as x and y=21 when x=7. which is an equation relating x and y

Mathematics
1 answer:
astra-53 [7]3 years ago
8 0
Y varies directly as x: y=kx, k is a constant.
when x=7, y=21, so we know k=3
therefore, the equation is y=3x
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Find an expression for the nth term ( tn ) in each of the following sequences:
Alexandra [31]

Answer:

The expression for the nth term is Tn = 8n -7

Step-by-step explanation:

Here, we are to find an expression for the nth term of the sequence.

Mathematically, the nth term of an arithmetic sequence can be expressed as;

Tn = a + (n-1)d

for T2, the equation is

a + d = 9

for T4, the equation is

a + 3d = 25

we can substitute the equation of T2 into T4 but we first need to rewrite T4

a + d + 2d = 25

9 + 2d = 25

2d = 25 -9

2d = 16

d = 16/2

d = 8

now since a + d = 9

a = 9-d

a = 9-8

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So the expression for the nth term would be;

1 + (n-1)8

1 + 8n - 8

= 8n -8+1

= 8n -7

6 0
3 years ago
A rectangular yard is 18 feet long. The area if the yard is 400.5 square ft. What is the width of the yard?
WARRIOR [948]

Answer:

22.25 feet wide

Step-by-step explanation:

A = lw

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22.25 = x

4 0
3 years ago
Find the area of a circle with a circumference of 12.56 units
vagabundo [1.1K]

Answer:

a = 157.7536pi

Step-by-step explanation:

area = pi*circumference²

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however, if pi just equals 3.14:

probably around 495.346304

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3 years ago
Read 2 more answers
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telo118 [61]

Answer:

£25185

Step-by-step explanation:

It depends on how many days are in your year. If it's a regular year, it's 365 days. If it's a leap year 366 days.

69 x 365 = 25185

69 x 366 = 25254

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igomit [66]

Answer:

2\frac{7}{8}

Step-by-step explanation:

23/8 As a mixed number is 2 7/8

As a decimal, 2.875

8 0
1 year ago
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