hi i need some help on a calculus question that i uploaded into my document section it is question number 26 i cannot seem to figure out part A or C so i am not able to solve part b im not sure how to solve for T in this question because x is given as 20 for part a i tried to take the derivative but it still leaves me with the T and i need to solve for T

26. the following formula was developed to describe the yield of syngas (V) in litres resulting from the heating of 100 g of sludge as a function of temperature (T) in Celsius and oxygen concentration (x) as a percent (for example, x=30 refers to a 30% concentration of oxygen in the reaction vessel).where {T | 300 T 800} and {x | 10 x 70}.

(a) Determine the maximum yield of syngas in an atmosphere of 20% oxygen. At what temperature does this occur?

(c) Determine the maximum yield of syngas at a temperature of 400 degrees C. At what oxygen concentration does this occur?

equation

V = 8 e^ 1 /8000(?+0.155x^25.22x507.8)^ 2

this is question number 26 from document i uploaded it may be clearer there