19 - a = 42

What is a?

Which equations represents circles that have a diameter of 12 units and a center that lies on the y-axis? check all that apply

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)

Sioux co. replaced the roof on its existing building, therefore increasing the building's life by 10 years. the cost of the roof is considered a(n):