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2 years ago

Find the sum. 10 + 12 + 14 + ... + 80

Mathematics

1 answer:

lyudmila [28]2 years ago

8 0

Answer:

1620

Step-by-step explanation:

The amount of even integers between 10 and 80 inclusive is 36 (5 for each interval of 10 [e.g., 10-19 has 5, 20-29 has 5] and one extra for 80).

Since the numbers are consecutive even numbers, we can use the fact that the sum of the numbers is equal to the average of the numbers, times the number of numbers.

The average of the numbers is 45, since $\frac{10+80}{2}=45$ . We can use only the two outer numbers to determine the average since the numbers are all evenly spaced as they are consecutive even numbers.

$45\times36=1620$ , so the sum is 1620.

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Which pair of lines is parallel? A. y=4x+1 and y+4=5 B. y=-2+x and 2y-2x=-2 C. y=1/4x + 2 and y-2=1/2x D. y=1/5x+1 and 5y+x= 10

sdas [7]

Answer:

B. y=-2+x and 2y-2x=-2

Step-by-step explanation:

Two lines are parallel if they have the same slope.

The equation 0of a line is tipically written as y=mx + b, where 'm' represents the slope and 'b' the y-intercept.

Let's evaluate each of the options:

A. y=4x+1 and y+4x=5

Writing the equations in the slope-intercept form, we get:

y=4x+1 → m=4

y=5-4x → m=-4

Given that they have different slopes, they are not parallel.

B. y=-2+x and 2y-2x=-2

Writing the equations in the slope-intercept form, we get:

y=-2+x → m=1

y=-1 + x → m=1

Given that the equations have the same slope, they are parallel.

C. y=1/4x + 2 and y-2=1/2x

Writing the equations in the slope-intercept form, we get:

y=1/4x + 2 → m=1/4

y=1/2x+2 → m=1/2

Given that they have different slopes, they are not parallel.

D. y=1/5x+1 and 5y+x= 10

Writing the equations in the slope-intercept form, we get:

y=1/5x+1 → m=1/5

5y+x= 10 → y=2 - 1/5x → m=-1/5

Given that they have different slopes, they are not parallel.

4 0

3 years ago

Is 3x + 2y = 6 a function??

professor190 [17]

Answer:

B :)

Step-by-step explanation:

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3 years ago

1. Your average daily balance on your charge card for the month of July is $855.28. If your card carries an annual interest rate

Nat2105 [25]

1. Using "exact" interest, your charge will be
.. I = Prt
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3. Your payment on 15,250 for 4 years will be $363.41. The effective interest rate that payment represents on a loan of $15,000 is 7.604%

4. Todd's monthly payments will be $409.06, so his total outlay will be
.. tax+license + down payment + loan repayment
.. = 1200 +1000 +48*409.06
.. ≈ $21,835