I need help:(

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

If 3x+8=3x+8 is it one solution or no solution

Mr. and mrs. wallace have decided to buy a car for $21,600. they finance $15,000 of it with a 5-year auto loan at 2.9% arp. what will be their monthly payment be? a. $268.20 b. $268.86 c. $269.54 d. $387.16 i need !