Integration by Substitution. The rate of growth of Grass carp, one of the most common type of fish, was modelled by the equation 5X+10 rm: 2 x +4x+3 where t is measured in years and t) in kilograms per year. Consider the integral 4 5x+1o 2d" 2 x +4x+3 After substitution into u, the new integral can be written 1) fidu ad (a) The value of A is (b) The upper limit of integration b is