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(c)

-9x^2 = 30x + 25   rearrange as

9x^2 + 30x + 25 = 0        we can factor this    !!!

(3x + 5) ( 3x + 5) = 0

Setting either factor to 0 and solving for x produces     x =  - 5/3

Please if you are going to say stuff like that please put it in off topic!

Second......Please this Forum is only for math questions!

Third.....This is very important you can only at least post two off topic post!! or the computer will flag you!

And you will not be able to post anything because it will say your post has gone invisable and that it needs to be seen by a moderator before being seen!

b )  x^2 + 41 = -8x

x^2 + 8x  =  -41      complete the square on x

x^2 + 8x + 16  =   -41 + 16

(x + 4)^2 =   - 25      take both roots

x + 4 =  ±√-25

x + 4 = ± 5i      subtract 4 from both sides

x =   - 4 ± 5i

1 pound = 453.592.37 gm

453 .59237 / 2.016  = 224.996 =~~225 moles     ( =  225 x 6.022 x 10^23  molecules  = 1.355 x 10^26 molecules)

135 lbs x  0.45359237 kg / 1 lb   x  0.5 mg / kg   x  ml /120 mg   ≈   0.255 ml  

-x^2+4x-13 = 0

x^2 - 4x + 13 = 0      Use quadratic formula  

\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)       a = 1  b  = -4   c = 13

Sustituting yields       4 +- sqrt( 16- 4*1*13)   /  2     =    2 +-sqrt (-36)/2    =  2 +-  3i

Think you can try the others?

Let's use consistent units     .75 l = 750ml

Density = mass/volume  =  765 gm / 750 ml  = 1.02   gm/ml

Urine density can change by the kindneys increasing the concentration....by excreting more salt ...or re-absorbing more water.

                                                            or decreasing the concentration by holding salt and excreting more water....

a)    1/x + 1 / 3x  = 6

        3/3x + 1/3x  = 6

        [ 4] / 3x = 6  multiply both sides by 3x

         4 =  18x       divide both sides by 18

         4/18 = x

         2/9 =   x

b)     1/x + 1 /x+1  = 3

         [ x + 1 + x ] / [ x ( x + 1) ] = 3

         [2x + 1 ] =  3 [ x ( x + 1) ]

         2x + 1  = 3 [ x^2 + x]

         2x + 1 =  3x^2 + 3x          rearrange as

         3x^2  + x - 1 = 0

Use the quad formula

x = [ -1 ±√ [ 1 - 4(3)(-1) ] / {2 * 3 ]

x =   [ -1 ±√13] / 6

c)   ( x +3 ) / ( x - 1)   -  x / (x + 1)  =    8 / [ (x + 1) ( x - 1) ]

Multiply through by  (x + 1) ( x - 1)

(x + 3)(x + 1)  - x(x - 1) =  8       simplify

x^2 + 4x  + 3  - x^2 + x = 8

4x + 3 + x = 8

5x + 3 = 8

5x = 5

x = 1

However....this makes a denominator = 0...so no solution exists

The first four ' - ' signs cancel out and you are left with

-10x = -5

x = 1/2= 0.5

135 lb  x   1kg/2.2lb  x  .5 mg/kg   /  120 mg/ml  = 0.256 ml

Why don't you do it yourself?

\(\sum \limits_{n=0}^\infty ~\alpha^n = \dfrac{1}{1-\alpha}\\ \text{here }\alpha = \dfrac 1 2\\ \text{and thus the sum is equal to }\dfrac{1}{1-\dfrac 1 2}= 2\)

Yes it all makes sense. thank you

help, so 5 kg*m/s was transferred?

okay sorry

when did you get so smart and where did you get so much knowledge?

x^5, a^3

Maybe right 

Not sure about this 

a)  t is the  time elapsed since the egg was dropped

b)  h(t) is the height at some time, t

c)  When it hits the ground, h(t) = 0

So....we can solve this

-16t^2 + 50 = 0  

-16t^2 = -50       divide both sides by -2

8t^2 =  25         divide both sides by 8

t^2 =  25/8  take the square root

t = √[25/8]  ≈ 1.77    sec

(d)  At 1 sec  the height is  -16(1)^2 + 50   =  34 ft

At 1.5 sec the height is  -16(1.5)^2 + 50   = 14 ft

So....it falls  34 -14   = 20 feet  in this time interval

In your previous posting, you stated how fast the 5 kg object was traveling after the collision.   We need that info here to solve this....if it is travelling at 20 m/s , I already answered this in the previous posting   

The conservation of momentum, means that before and after the collision, the momentum totals are the same...

original momentum    5 kg * 25 m/s = 125  kg -m/s

After collision             5      *20 =          100 kg-m/s

this means that the 1 kg object has the remainder of the momentum   and is traveling at 25 m/s