The rate of residential electricity consumption (in billions of kilowatt hours (kwh) per year) of a country is approximated by the model below, where x=0 corresponds to the year 1990. find the total consumption of electricity from 2001 to 2006.

Congrats on making it to integrals!
Basically you need to integral your function because integral rate in respect to time = total amount.
Also your bounts are (2001-1990,2006-1990)=(11,16)

Thus we take integral like:
int(11,16)(928.5e^(0.0249x))=
(11,16)928/0.0249e^(0.0249(x))-928/0.0249e^(0.0249(x))
(You can check this by taking its derivative and seeing if you get the original function)
928/0.0249e^(0.0249(16))-928/0.0249e^(0.0249(11))=6498.1