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lbvjy [14]
3 years ago
15

What is the sum of the first 4 terms of the arithmetic

Mathematics
1 answer:
liraira [26]3 years ago
8 0
a_6=8;\ a_{10}=13\\\\a_{10}-a_6=4r\\\\4r=13-8\\4r=5\ \ \ \ /:4\\r=1.25\\\\a_1=a_6-5r\\a_1=8-5\cdot1.25=8-6.25=1.75\\\\S_4=\frac{2a_1+(4-1)r}{2}\cdot4=(2a_1+3r)\cdot2=4a_1+6r\\\\S_4=4\cdot1.75+6\cdot1.25=7+7.5=14.5
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A bacteria culture initially contains 100 cells and grows at a rate proportional to its size. After an hour the population has i
Assoli18 [71]

Step-by-step explanation:

Rate of growth equals 420/100 = 4.2 times per hour

So after t=three hours,

size of culture = 100*(4.2)^t = 100*4.2^3=7408.8 bacteria,

round to nearest unit 7409 bacteria after three hours (after initial size of 100).

8 0
2 years ago
Read 2 more answers
If the ratio of three angles of a triangle is 2:3:4 find the size of the largest angle​
Murljashka [212]
Answer: 80°

Step-by-Step Explanation:

By Angle Sum Property of a Triangle, all angles in a Triangle add up to 180°

Finding the Value of ‘x’ :-

2x + 3x + 4x = 180
5x + 4x = 180
9x = 180
x = 180/9
=> x = 20

Finding each Angle :-

2x = 2(20) = 2 * 20 = 40°
3x = 3(20) = 3 * 20 = 60°
4x = 4(20) = 4 * 20 = 80°

Hence, the Largest Angle is 80°
3 0
1 year ago
I really need on these cause I really don't know this and I need to understand. please help me please.​
lawyer [7]

Answer:

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Step-by-step explanation:

First you move the parenthesis then you group the like terms after you group the like terms you get m^4-7m^4-m^3 which is adding the similar elements and after you add similar elements you get  -6m^4-m^3. Srry if this makes no sense

8 0
3 years ago
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Prove the polynomial identity. (2x−1)2+2(2x−1)=(2x+1)(2x−1) Drag and drop the expressions to correctly complete the proof of the
Alex_Xolod [135]

Answer:

Step-by-step explanation:

Given expression is,

(2x - 1)² + 2(2x - 1) = (2x - 1)(2x + 1)

To prove this identity we will take the left hand side of the equation and will prove equal to the right side.

(2x - 1)² + 2(2x - 1) = (2x - 1)(2x + 1)

4x² - 4x + 1 + 4x - 2 = (2x - 1)(2x + 1)

4x² - 1 = (2x - 1)(2x + 1)

(2x - 1)(2x + 1) = (2x - 1)(2x + 1) [Since a² - b² = (a - b)(a + b)]

6 0
3 years ago
I need help please thank you hurry
Elena-2011 [213]

Answer:

Step-by-step explanation:

To get the other angles you need to do this

110+80+x+x=360

190+2x=360

2x=360-190

2x=170

X=170÷2

X=85

5 0
3 years ago
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