6 songs
The way to find this answer is to divide 18 by 3, which is six, which means that after every six songs a commercial is played.
Hope this was helpful and that I explained it correctly.
Answer: see proof below
<u>Step-by-step explanation:</u>

Use the following Identities:
sec Ф = 1/cos Ф
cos² Ф + sin² Ф = 1
<u>Proof LHS → RHS</u>






Answer:
50
Step-by-step explanation:
because 3,650-3,500=150 and then 150/12=12.5x4=50
Answer: plot a point at (-8, -5)
The y coordinate flips from positive to negative, or vice versa, when we reflect over the horizontal x axis. The x coordinate stays the same.
The rule can be written as 
Answer: <span>D. Are perpendicular
</span><span>4x=3y+23 slope = 4/3
</span><span>4y+3x=-19 slope = -3/4</span>