1. which of the following statements is true regarding the use of refrigerants?
a) records of the dates and quantities of refrigerant recovered and recycled are unnecessary
b) filters from approved refrigerant equipment can be thrown in the trash
c) recover and recycle refrigerant using epa-approved equipment
d) if your equipment is recovery only, refrigerant that is removed from vehicles should be poured down the drain

Write a program that uses a widgetviewer object to do the following: generate two random integers between 1 and 9 (inclusive). name one of them x, the other y. display them to the user using jlabel objects. create a jlabel object displaying the text "enter an operation number." create a jtextfield for the user's input. create a jbutton displaying the text "press here when you've entered your operation." use addandwait to add it to the widgetviewer object. when the user clicks the jbutton, evaluate operation in the following order to determine the one and only mathematical operation to perform on x and y. use a jlabel to display the result. if operation is between 1 and 10 inclusive, add x and y. if operation is evenly divisible by 4, subtract y from x. if operation is evenly divisible by 5, use integer division to divide y into x. if operation is an even number, use floating point division to divide y into x. if none of the other tests on operation apply, multiply x and y. note: operation can be negative or zero.

1. technician a says horsepower information can be used by consumers to compare the power of different automobile engines. technician b says that manufacturers will often list the horsepower output of their engines in the online service information. who is right?

Need ! will choose brainliest! discuss the role of abstraction in the history of computer software.