Which equation best represents the amount of money the store makes if x shirts are solid

What is the value of x? enter your answer in the box. photo attached.

Which point on the x-axis lies on the line that passes through point c and is parallel to lino ab?

If the speed of an electromagnetic wave is 100,000 cm/s and its wavelength is 100 cm, what is its frequency? a) 100,000 cycles per second (hz) b) 1 × 10-3 cycles per second (hz) c) 10,000,000 cycles per second (hz) d) 1,000 cycles per second (hz)