Which similarly statement is true?

Successful implementation of a new system is based on three independent modules. module 1 works properly with probability 0.96. for modules 2 and 3, these probabilities equal 0.95 and 0.90. compute the probability that at least one of these three modules fails to work properly.

Just tell me how to set up the equation.

Find the solution of this system of equation -7x+y=-20 9x-3y=36