The coefficients corresponding to k=0,1,2...,5 in the expansion of (x+y)^5 are?

How do i do this? i don’t understand

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.

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?