2. Use the choose-an-element method to prove each of the following: (a) ˚ x 2 R j x 2 3x 10 < 0 D fx 2 R j 2 < x < 5g (b) ˚ x 2 R j x 2 5x C 6 < 0 D fx 2 R j 2 < x < 3g (c) ˚ x 2 R j x 2 4 D fx 2 R j x 2g [ fx 2 R

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.