Is this a pythagorean triple? 40,55,90

Alawn mower manufacturer incurs a total of 34,816 in overhead costs and 388 per lawn mower in production costs. how many lawn mowers were manufactured if the average cost of productions is 660

What expression is equivalent to (2x-1)(x-3)?

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)