Slope of 4,-9 and 8,-3

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.

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0

1/2+1/6-3/4 simplify the given expression leaving the answer in improper fraction form.