HELP PLEASE!
Over two summers, Ray saved $900 and $500. The polynomial 900x^2 + 500x represents his savings at the beginning of the third year, where x is the growth factor. (The interest rate r is x - 1.) What is the interest rate he needs to start the third year with $1600 in savings?
A. 1.1%
B. 0.1%
C. 8.4%
D. 264%

Question

HELP PLEASE!
Over two summers, Ray saved $900 and $500. The polynomial 900x^2 + 500x represents his savings at the beginning of the third year, where x is the growth factor. (The interest rate r is x - 1.) What is the interest rate he needs to start the third year with $1600 in savings?
	A. 1.1% 	
	B. 0.1% 	
	C. 8.4% 	
	D. 264%

jim_thompson5910 · Answer

He has 900x^2 + 500x in savings in the third year

jim_thompson5910 · Answer

He needs $1600, so

900x^2 + 500x = 1600

jim_thompson5910 · Answer

Solve that for x and tell me what you get

jim_thompson5910 · Answer

The answer you get for x can then be plugged into x-1 to find the interest rate