It is already in identity.
cos (x - y) - cos (x + y) = 2 sin(x) sin (y)
Minus 9x from both sides
-3y=-9x+12
divide both sides by -3
y=3x-4
$1.79 i hope this helps you
Answer:
rs 38.
Step-by-step explanation:
Total cost of the 80 books = 80*30 = rs 2400.
He had 60 books to sell and made a 5% loss.
Thus his income from these books was 2400 - 0.05*2400 = rs 2280.
So the selling price of each book was 2280 / 60 = rs 38.
