help!!!Maths(2)

a) Solve the equation log'base6'(x+3)+log'base6'(x+4)=1

b) A company plans to transport x printers and y computers in a van. The van can carry a maximum load of 180 kg of goods and a maximum volume of 3 m^3 is available. It is known that each printer weighs 12 kg and occupies 0.1 m^3 of space while each computer weighs 18 kg and occupies 0.4 m^3 of space. The company can make a profit of $100 per printer and $200 per computer.

(i) Write down all the constraints on x and y.
(ii) Express the profit (P) in terms of x and y.
(iii) What should be the values of x and y so that the profit is maximized?