Can someone help me please

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

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 !

Mackenzie needs to determine whether the rectangles are proportional. which process could she use? check all that apply.