If dy/dx = -10y and if y = 50 when x = 0, then y = (a) 50cos10x (b) 50e^(10x) (c) 50e^(-10x) (d) 50 - 10x (e) 50 - 5x^2
Have you come across the technique of separating variables yet?
for your problem we have
divide through by y and integrate both sides with respect to x
giving us
do the integration leaving us with
I'll leave you to finish it off and plug in the boundary condition