1. x - 3 = 7 2. 8w = 48 3. 9 + y = 100 4. a/2 = 18 show work plz

(a) calculate the molarity of a solution that contains 0.0345 mol nh4cl in 400 ml of solution. (b) how many moles of hno3 are present in 35.0 ml of a 2.20 m solution of nitric acid? (c) how many milliliters of 1.50 m koh solution are needed to supply 0.125 mil of koh ?

Which graph represents the following piecewise defined function?

How to do this , and can some one explain