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gayaneshka [121]
3 years ago
8

Please help

Mathematics
1 answer:
ASHA 777 [7]3 years ago
5 0

Answer:

(-6,4)

Step-by-step explanation:

The equations are:

x^2+4y^2=100\\4y-x^2=-20

Solving for x^2 of the 2nd equation and putting that in place of x^2 in the 2nd equation we have:

4y-x^2=-20\\x^2=4y+20\\-------\\x^2+4y^2=100\\4y+20+4y^2=100

Now we can solve for y:

4y+20+4y^2=100\\4y^2+4y-80=0\\y^2+y-20=0\\(y+5)(y-4)=0\\y=4,-5

So plugging in y = 4 into an equation and solving for x, we have:

x^2=4y+20\\x=+-\sqrt{4y+20} \\x=+-\sqrt{4(4)+20} \\x=+-\sqrt{36} \\x=6,-6

So y = 4 corresponds to x = 6 & x = -6

The pairs would be

(6,4) & (-6,4)

<u><em>we see that (-6,4) falls in the 2nd quadrant, thus this is the solution we are looking for.</em></u>

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Grace [21]
While you didn't post the instructions for this problem, I can safely assume that you're supposed to factor 8x^2 - 8x - 30.

First, note that all of these terms can be divided by 2:

8x^2 - 8x - 30 = 2(4x^2 - 4x - 15)

Inside the parentheses is a quadratic equation which can't be reduced further.  There are a good number of methods that you could use to solve this quadratic:

graphing, completing the square, factoring, quadratic formula, and so on.

I note that the first and last coefficients are 4 and 15.

Thus, possible roots are:

numerator           1, 3, 5, 15, -1, -3, -5, -15
------------------ = -----------------------------------
denominator        1, 2, 4, -1, -2, -4

For example, one root might be -5/2 (-5 from the numerator and 2 from the denominator).

Let's check whether -5/2 is actually a soluion, using synthetic div:

            ___________________
  -5/2   /   4        -4      -15
                        -10      7/2
                  __________________
               4       -14      Remainder is NOT zero, so -5/2 is not a root.

Lots of possibilities here.

Thus, I'm going to resort to the good old Quadratic Formula to determine the 
factors of 4x^2 -4x - 15:

a=4, b= -4 and c = -15

Then the the roots are:

         4 plus or minus sqrt(16-4(4)(-15)
x = ------------------------------------------------
                               8
        4 plus or minus sqrt(256)        4 plus or minus 16
   = ------------------------------------- = -------------------------------
                                8                                 8

    = 20/8 and -12/8, or 5/2 and -3/2

Thus, in factored form the polynomial is 8(x-5/2)(x+3/2)
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3 years ago
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Pavlova-9 [17]

Answer:

193.8

Step-by-step explanation:

a = 3.8 times 10^13 = 38,000,000,000,000

b = 5.1 times 10^-12 = 0.0000000000051

a times b = 193.8

7 0
3 years ago
Oliver is working with square tiles that are 3/4 inch on each side. What is the area of each tile?
likoan [24]

Answer:

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Step-by-step explanation:

4 0
3 years ago
A spherical hot-air balloon has a diameter of 55 feet. When the balloon is inflated, the radius increases at a rate of 1.5 feet
abruzzese [7]

Answer:

The time it would take to inflate the balloon to approximately two-thirds of its maximum volume is approximately 46.90 minutes

Step-by-step explanation:

The given parameters are;

The diameter of  the balloon  = 55 feet

The rate of increase of the radius of the balloon when inflated = 1.5 feet per minute

We have;

dr/dt = 1.5 feet per minute = 1.5 ft/min

V = 4/3·π·r³

The maximum volume of the balloon = 4/3 × 3.14 × 55³ = 696556.67 ft³

When the volume is two-thirds the maximum volume, we have;

2/3 × 696556.67 ft³ = 464371.11 ft³

The value of the radius, r₂ at that point is found as follows;

4/3·π·r₂³ = 464371.11 ft³

r₂³ = 464371.11 ft³ × 3/4 = 348278.33 ft³

348278.333333

r₂ = ∛(348278.33 ft³) ≈ 70.36 ft

The time for the radius to increase to the above length = Length/(Rate of increase of length of the radius)

The time for the radius to increase to the above length ≈ 70.369 ft/(1.5 ft/min) ≈ 46.90 minutes

The time it would take to inflate the balloon to approximately two-thirds of its maximum volume ≈ 46.90 minutes.

4 0
3 years ago
Help me w math, need it ASAP ​
Alex17521 [72]

Answer:

Step-by-step explanation:

See attached image.

6 0
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