Solve for x round to the nearest tenth

Me find the measure to side c and the process to solve the problem you appreciate it : )

(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 is the graph of the function y=2(4)^x