The hardcover version of a book weighs 7 ounces while its paperback version weighs 5 ounces. Forty-five copies of the book weigh a total of 249 ounces.
| Weight of Books |
|---------------------------------------|
| Number of Books | Weight per book (ounces) | Total Weight (ounces) |
| Hard Cover | h | 7 | 7h |
| Paperback | 45-h | 5 | x |
| Total | 45 | | 249 |
Which value could replace [tex]$x$[/tex] in the table?
A. [tex]$40-h$[/tex]
B. [tex]$50-h$[/tex]
C. [tex]$5(45)-h$[/tex]
D. [tex]$5(45-h)$[/tex]
Answer (3)
LHS is nothing but (using sin (a+b) = sin a cos b + cos a sin b)
sin (x+2x) = sin 3x = 0
so 3x = npi
or
x = npi/3
The answer is x = n p i divided by 3
To solve sin x cos 2 x + cos x sin 2 x = 0 , we rewrite it as sin ( 3 x ) = 0 . The solutions are given by x = 3 nπ , or in degrees, x = 0° , 60° , 120° , 180° , 240° , 300° , … .
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