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wel
3 years ago
6

S=n/2(2a+(n-1)d). If d=5, n=13, S=585 find the value of a.​

Mathematics
1 answer:
anygoal [31]3 years ago
7 0

Answer:

15

Step-by-step explanation:

Sum of 'n' terms formula is given by:-    

s=n/2(2a+(n-1)d)  

s=13/2[2xa+(13-1)5]    

s=13/2(2xa+12x5)    

s=13/2(2a+60)    

585=13/2(2a+60)    

585 x (2/13) = 2a + 60

90 = 2a + 60  

90-60 = 2a

30 = 2a

a = 15

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(18x-44 )(8x-10) (13y-38) geometry
xenn [34]

Simplifying

18x + -44 = 13y + -38

Reorder the terms:

-44 + 18x = 13y + -38

Reorder the terms:

-44 + 18x = -38 + 13y

Solving

-44 + 18x = -38 + 13y

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '44' to each side of the equation.

-44 + 44 + 18x = -38 + 44 + 13y

Combine like terms: -44 + 44 = 0

0 + 18x = -38 + 44 + 13y

18x = -38 + 44 + 13y

Combine like terms: -38 + 44 = 6

18x = 6 + 13y

Divide each side by '18'.

x = 0.3333333333 + 0.7222222222y

Simplifying

x = 0.3333333333 + 0.7222222222y

3 0
3 years ago
A resturant sells 10 tacos for 8.49,or 6 of the same kind of taco for 5.40.Which is a better deal
Aliun [14]

Answer:

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3 0
3 years ago
The cost of raincoat is rs 400 and VAT is rs 40 find the rate of VAT​
DaniilM [7]

Divide vat by price

40/400 = 0.1

Multiply by 100

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5 0
3 years ago
Given that Triangle ABC such that<br>a=8cm, b=7cm and c=9cm<br>tem and c= 9cm find Cos B​
charle [14.2K]

Answer:

We use cosine rule also called cosine law which states

c^2=a^2+b^2-2abcosC

given

a=8cm, b=7cm, c=9cm cos C?

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expand

81=64+49-112 cos C

like terms together

81-113=-112 cos C

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multiply both sides by -1

32=112cos C

divide both sides by 112

32/112=cos C

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find cos inverse of 0.2857

angle C= 73.40

4 0
3 years ago
Write the denominator of the fractiona 7/20 as the product of prime factors
gtnhenbr [62]

Answer:

Step-by-step explanation:

prime factors of 20 = 2 * 2 * 5

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5 0
3 years ago
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