If the equation (1+m^2)x^2+2mcx+c^2-a^2=0 has equal roots, show that c^2=a^2(1+m^2)​

The oates family went out for dinner the price of the meal was $33.95 the sales tax was 7.25% of the price of the meal . the tip was 15% of the meal and the sales tax . how much money did the oates family pay for the meal, including tax and tip