Write the expression as the sine, cosine, or tangent of an angle. cos 9x cos 6x - sin 9x sin 6x

O cos 3x
O sin 15x
O cos 15x
O sin 3x

Step-by-step explanation:

cos 9x cos 6x - sin 9x sin 6x = cos (9x+6x)

= cos 15x

1) c 2143.6 cm

2) c 113.0 m

3) a 33.5 ft

4)   d 2 cm

5) c 20 mm

6) 180 in

7) d 120 ft

answer:

it is 28 degrees colder in detroit than philadelphia.

step-by-step explanation:

what number adds to 21  

-7 + ? = 21

-7 + 28 = 21

hope it