book Maths Puzzle Numerical Ability

Furst of all, thank you for all the recent help-I think I may be getting this, but, of course, something else has come up and has stopped me. May I ask for help with this?:
in sol

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book Other Question

(-4)(7)+(-4)(-9) Use this equation to solve the following:

A = C multiplied by 2 with an exponent of -t/T




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