Recall that the symbol z represents the complex conjugate of z. if z = a + bi, show that the statement is true. z − z is a pure imaginary number. use the definition of complex conjugates to simplify the expression.

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 3 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30∘c on monday, but decreased at a constant rate in the next 3 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.