Is this app in solving precalculus problems?

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.

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much

What value is a discontinuity of x squared plus 8 x plus 4, all over x squared minus x minus 6?