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3 years ago

Prove that the gregorian calendar repeats itself every 400 years.

1 answer:

3 0

The calendar obviously has an integral number of years and months in 400 years. If it has an integral number of weeks, then it will repeat itself after that time. The rules of the calendar eliminate a leap year in 3 out of the four century years, so there are 97 leap years in 400 years. The number of excess days of the week in 400 years can be found by ...

(303·365) mod 7 + (97·366) mod 7 = (2·1 + 6·2) mod 7 = 14 mod 7 = 0

Thus, there are also an integral number of weeks in 400 years.

The first day of the week is the same at the start of every 400-year interval, so the calendar repeats every 400 years.

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Hat is the equation of the quadratic function with a vertex at (2,–25) and an x-intercept at (7,0)?

Novosadov [1.4K]

Answer:

y = x² - 4x - 21

Step-by-step explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

Here (h, k) = (2, - 25), thus

y = a(x - 2)² - 25

To find a substitute (7, 0) into the equation

0 = a(7 - 2)² - 25 = a(5)² - 25 = 25a - 25 ( add 25 from both sides )

25a = 25 ( divide both sides by 25

a = 1, thus

y = (x - 2)² - 25 ← in vertex form

Expand and simplify

y = x² - 4x + 4 - 25

y = x² - 4x - 21 ← in standard form

8 0

3 years ago

Mr.James has a cylindrical beakers that measure 4 inches in diameter and are 9 inches high .What is the volume contained within

Ksju [112]

Cylinder Volume = PI * radius^2 * height

Cylinder Volume = 3.14 * 2^2 * 9

Cylinder Volume = 113.04 cubic inches

1728.com/diamform.htm

8 0

4 years ago

Read 2 more answers

Can someone plz help me with this!

asambeis [7]

Answer:

(arranged from top to bottom)

System #3, where x=6

System #1, where x=4

System #7, where x=3

System #5, where x=2

System #2, where x=1

Step-by-step explanation:

System #1: x=4

$2x+y=10\\x-3y=-2$

To solve, start by isolating your first equation for y.

$2x+y=10\\y=-2x+10$

Now, plug this value of y into your second equation.

$x-3(-2x+10)=-2\\x+6x-30=-2\\7x=28\\x=4$

System #2: x=1

$x+2y=5\\2x+y=4$

Isolate your second equation for y.

$2x+y=4\\y=-2x+4$

Plug this value of y into your first equation.

$x+2(-2x+4)=5\\x+(-4x)+8=5\\x-4x+8=5\\-3x=-3\\x=1$

System #3: x=6

$5x+y=33\\x=18-4y$

Isolate your first equation for y.

$5x+y=33\\y=-5x+33$

Plug this value of y into your second equation.

$x=18-4(-5x+33)\\x=18+20x-132\\-19x=-114\\x=6$

System #4: all real numbers (not included in your diagram)

$y=13-2x\\8x+4y=52$

Plug your value of y into your second equation.

$8x+4(13-2x)=52\\8x+52-8x=52\\0=0$

<em>all real numbers are solutions</em>

System #5: x=2

$x+3y=5\\6x-y=11$

Isolate your second equation for y.

$6x-y=11\\-y=-6x+11\\y=6x-11$

Plug in your value of y to your first equation.

$x+3(6x-11)=5\\x+18x-33=5\\19x=38\\x=2$

System #6: no solution (not included in your diagram)

$2x+y=10\\-6x-3y=-2$

Isolate your first equation for y.

$2x+y=10\\y=-2x+10$

Plug your value of y into your second equation.

$-6x-3(-2x+10)=-2\\-6x+6x-30=-2\\-30=-2$

<em>no solution</em>

System #7: x=3

$y=10+x\\2x+3y=45$

Plug your value of y into your second equation.

$2x+3(10+x)=45\\2x+30+3x=45\\5x=15\\x=3$

3 0

3 years ago

What is the sum of the interior angles of a hexagon?

Gala2k [10]

Hello!

So, every interior angle of a regular hexagon measures 120 degrees.

There are six interior angles of a hexagon, so you have to multiply 120 by 6.

120 x 6 = 720

So, the answer to your question is that the sum of the interior angles of a hexagon is 720 degrees.

Hope this helps!

3 0

3 years ago

Analyze the diagram below Need CORRECT ANSWER BELOW!!!

Zarrin [17]

Answer:

D. 8

Step-by-step explanation:

The given diagram is a trapezium. We know that the consective sides of a trapezium are equal. so,

Putting the values of consecutive sides equal:

So, KI will be equal to LI

3x-7 = x+3

$3x-7-x=x+3-x\\2x-7=3\\2x-7+7=3+7\\2x=10\\x=5$

Putting the value of x in the equation of KI

3x-7

=3(5)-7

=15-7

Hence, the correct answer is D. 8 ..

6 0

3 years ago