How do u write a ratio in simplest form for 42/28

The lines shown below are parallel. if the green line has a slope of -1, what is the slope of the red line?

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

Witch represents the inverse of the function f(x)=1/4x-12