What two numbers sum up to 11 and multiply to 18

What number produces an irrational number when multiplied by -1.25

Arefrigeration system at your company uses temperature sensors fixed to read celsius (°c) values, but the system operators in your control room understand only the fahrenheit scale. you have been asked to make a fahrenheit (°f) label for the high temperature alarm, which is set to ring whenever the system temperature rises above –10°c. what fahrenheit value should you write on the label

Which system of linear inequalities is represented by the graph?