Question 42340
850 = r*t
r = 850/t
850 = (r+5)(t-2)
850 = rt + 5t - 2r - 10
850 = t*(850/t) + 5t - 2(850/t) - 10
850 = 850 + 5t - 1700/t -10
-850 = -850
0 = 5t - 1700/t -10
5t - 1700/t = 10
5t^2 -1700 = 10t
5t^2 - 10t - 1700 = 0
t^2 - 2t - 340 = 0
use quadratic formula to find t
then use 850 = rt to find r
at^2 + bt + c = 0
{{{t = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}