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3 years ago

How to classify this conic ecwation 4x^2+9y^2-54y-63=0

1 answer:

6 0

This looks like an ellipse.
Complete the square for y: 9(y²-6y-7)=9(y²-6y+9-9-7)=9((y-3)²-16).
Rewrite the equation:
4x²+9(y-3)²-144=0; 4x²/144+9(y-3)²/144=1; x²/36+(y-3)²/16=1.
Standard equation of an ellipse is (x-h)²/a²+(y-k)²/b²=1, where (h,k) is the origin or centre.
This is the equation of an ellipse with centre (0,3), a=6 and b=4 (semimajor and semiminor axes).

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Which ratio is proportional to 18/28 ? <br> Help me plzzzz i will give brainliest

maks197457 [2]

Answer:

18/21 = 30/35

Step-by-step explanation:

so the problem says 18/21 so if that's the correct ratio to proportion to the answer would be. 30/35. the reason is that you can divide 18 and 21 by 3 to get 6/7 then if you multiply by 5 you get 30/35. Dividing and multiplying both the denominator and numerator keeps the ratio proportional.

3 0

3 years ago

The average weight of the class of 35 students was 45 KG. with the admission of a new student the average weight came down to 44

melamori03 [73]

The weight of the new student is 27 kg.

Average weight

= total weight ÷total number of students

<h3>1) Define variables</h3>

Let the total weight of the 35 students be y kg and the weight of the new student be x kg.

<h3>2) Find the total weight of the 35 students</h3>

y= 35(45)

y= 1575 kg

<h3>3) Write an expression for average weight of students after the addition of the new student</h3>

New total number of students

= 35 +1

= 36

Total weight

= total weight of 35 students +weight of new students

= y +x

$44.5 = \frac{y + x}{36}$

<h3>4) Substitute the value of y</h3>

$44.5 = \frac{1575 + x}{36}$

<h3>5) Solve for x</h3>

36(44.5)= 1575 +x

1602= x +1575

<em>Subtract 1575 from both sides:</em>

x= 1602 -1575

x= 27

Thus, the weight of the new student is 27 kg.

7 0

3 years ago

Which number produces a rational number when multiplied by 0.5?

xxMikexx [17]

If the number begins by being rational, multiplying by 0.5 will not change whether or not it is rational. It will remain rational.

That would include any even number 12 * 0.5 = 6

12 started out as rational, so the answer is rational (6)

Any odd number is also rational

23 * 0.5 = 11.5

23 and 11.5 are both rational.

3.636363636 ... is rational so when multiplied by 0.5 the result will be rational.

1.818181818....

So if we start with something irrational like pi

then pi * 0.5 is not rational.

If you have choices, please list them.

4 0

3 years ago

Write:<br> 3^-4 in standard form

pav-90 [236]

Answer:

$\frac{1}{81}$

Step-by-step explanation:

<u>Key skills: Exponents + Fractions</u>

Use the negative exponent property. If your number is x^-y then it would be the same as 1/x^y

3^-4 is the same as $\frac{1}{3^{4}}$

3^4 is 81, so your answer would be 1/81.

Hope you have a nice day and understood this!

4 0

3 years ago

Given f(x) = x^2-3 and g(x)=x+2/x. Find (g°f)(4)

goblinko [34]

Answer:

15/13

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers