Ineed the formula not the answer

x^{2} [/tex]> 49

Mr and mrs smith buy tickets for themselves and their four children. the cost of an adult ticket is ? 6 more than the adult ticket. the total cost of the six tickets is ? 40.50 work out the cost of an adult ticket. in your working let c be the cost of the child ticket and a be the cost of the adult ticket.

Just tell me how to set up the equation.

What expression is equivalent to 42x-56y