Which postulate proves??? Please help.

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?

Find the condition that the zeros of the polynomial f(x) = x^3+3px^2+3px+r may be in a.p.

What is the area of the shaded sector?