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aev [14]
3 years ago
8

For what values of K does x2+kx+9=0

Mathematics
1 answer:
Airida [17]3 years ago
4 0

Answer:

k = 6

Step-by-step explanation:

x {}^{2}  + kx + 9 = 0

here,

a = 1,

b = k

c = 9

now,

D = b {}^{2}  - 4ac

k {}^{2}  - 4(1)(9) = 0 \\   k {}^{2}  - 36 = 0 \\ k {}^{2}  = 36 \\ k = 6

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A square has an area of 100 square meters.<br> What is the perimeter of the square?
LiRa [457]

Answer:

40 square meters

Step-by-step explanation:

Perimeter means to add up all sides.

area means one side times one side

10 times 10 makes 100 so i am guessing each side is 10

10 + 10 + 10 + 10 = 40

5 0
3 years ago
Let a=3/5 and let b=2/3. Compute a^2b^-3.
Amanda [17]

Answer: 81/100



Step-by-step explanation:

I don't guarantee you I am right but..

first, solve for the exponents after substituting the numbers in

3/5 x 3/5 is 9/25

since b's exponent is negative, you change the fraction into its reciprocal and then do it with the exponent but positive

2/3^-3 to 3/2^3 and 3/2 x 3/2 is 9/4

then you mutiply both numbers to get 9/4 x 9/25 is 81/100

7 0
2 years ago
Someone please help!
valentina_108 [34]

Answer:

x = 33

Step-by-step explanation:

8 0
2 years ago
Dante and Mia have a total of 350 pennies in their piggy banks, altogether. After Dante lost half of his pennies and Mia lost on
tatuchka [14]

Answer:

150 pennies were lost altogether

Step-by-step explanation:

Let the initial number of pennies owned by Dante be x pennies

Let the initial number of pennies owned by Mia be y pennies

Mathematically ;

x + y = 350 •••••••(i)

So after losing half, dante will have x/2 pennies left.

Mia lost 1/3 so she will have 2/3y left

So after all the losses, they both had equal amount of pennies

This means that;

x/2 = 2y/3

Cross multiply;

3x = 4y •••••••(ii)

Let’s solve both equations simultaneously;

From i , x = 350-y

Substitute this into equation ii

3(350-y) = 4y

1050-3y = 4y

7y = 1050

y = 1050/7

y = 150

since x = 350-y

x = 350-150 = 200

Now Dante loss x/2 = 200/2 = 100

Mia lost 1/3y = 1/3 * 150 = 50

Total pennies lost = 100 + 50 = 150

7 0
3 years ago
Solve the equation cot 2x + cot x =3
rusak2 [61]

tan2x*cotx - 3 = 0

We know that: tan2x = sin2x/cos2x and cotx = cosx/sinx

==> sin2x/cos2x *cosx/sinx = 3

Now we know that sin2x = 2sinx*cosx

==> 2sinxcosx/cos2x * cosx/sinx = 3

Reduce sinx:

==> 2cos^2 x/ cos2x = 3

Now we know that cos2x = 2cos^2 x-1

==> 2cos^2 x/(2cos^2 x -1) = 3

==> 2cos^2 x = 3(2cos^2 x -1)

==> 2cos^2 x = 6cos^2 x - 3

==> -4cos^2 x= -3

==> 4cos^2 x = 3

==> cos^2 x = 3/4

==> cosx = +-sqrt3/ 2

<span>==> x = pi/6, 5pi/6, 7pi/6, and 11pi/6</span>

3 0
3 years ago
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