CPhill

Let the  number  of paperback  books  = x

Then the number  of hardcover books  = 25  - x

So.....we  have

number of hardcover * cost each  +  number of paperbacks * cost each = total cost

So

(25  - x) * 1.50  +  x * .50   =   26.50     simplify

37.5 -1.50x  +  .50x   = 26.50

37.5  -  x  =  26.50     subtract   37.5  from both sides

-x  =  -11     multiply thrugh by  -1

x  =11  =  number  of paperbacks purchased

Jenny, I don't understand a word of this.....but, depending upon what you might trust, here's what this website says  :

https://www.westfield.ma.edu/PersonalPages/cmasi/gen_chem2/imf/phase_changes/ke_vs_imf.htm

Just  multiply  the  numerartors  and denominators

Ex :

3        5               15

__  *  __  =          __

8        7               56

Note.....  reducing  before we multiply can make it easier  [and puts the result in lowest terms  ]

Ex :

3       6                1        1           1

__ * ___    =      __  *   ___  =   ___

 6     24               2         4           8

We can use  the Law of Cosines to find the measure  of  the  smaller angle, A

2.9^2  = 4^2  + 4^2  - 2 (4)(4) cos  A

[2.9^2 - 4^2  - 4^2  ]  / [ -2 (4) (4)  ]  =  cos A

Using the  inverse  cosine  we  have that

arccos ( [2.9^2 - 4^2  - 4^2  ]  / [ -2 (4) (4)  ] )  = A  = 42.51°

And the larger  angle   is supplemental to this  =   180 - 42.51   =  137.49°  ≈  137.5°

Since one standard deviation  = 10

Then  the given range of 50-70 falls within   1 standard  deviation  on  either side  of  the mean

Approxinatelt  34.13%   of the  measurements fall  within one standard deviation on either side of the mean

So  2  [34.13% ]  =  64.26%  of the days have  between 50  and 70  customers

Under the translation T(-1, 2) the point (-2, 3) will become (-3, 1).

Just add the  coordinates of T  to the given point and we have

[ -2  - 1 , 3 + 2  ] =   ( -3 , 5)   →  False

Given NLM → POM, the image of point L is point O.

True

N maps to P

L maps to O

M maps to M

Given NLM → POM, the image of angle MLN is angle MOP.

True

See if you can figure  out the last one from my first answer

(a)   P ( a win)   = 1 / C(36, 6)  =  1 / 194772 

From 7 to 8  there are  6 10-minute periods....so,,,,,

At  8PM...there are...1000  + 6(15)   = 1000 + 90  = 1090  home fans

At 8 PM  there  are   700 - 6(5)      =  700  - 30  =  670  away fans

Home  /  Away    =     1090  /  670   =   109  /  67

See here. oscar  :

https://web2.0calc.com/questions/help-please_22397

Let S  = cost to download a  song  and A  = cost to  download an album

We have this system

5S  + 1A =  14.94   ⇒    A  = 14.94   - 5S       (1)

3S  +  2A =  22.95                  (2)

Sub  (1) into (2)   for    A  and we  have  that

3S  + 2 [ 14.94  - 5S   ]=   22.95      simplify

3S  + 29.88 - 10S   = 22.95

-7S + 29.88 =  22.95          subtract  29.88 from  both  sides

-7S = -6.73    divide  both  sides  by  7

S  = .99    = cost to  download a song