Help please i’ll give brainliest :,)

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Find the roots of the equation below. x^2 - 6 + 9 = 0

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 33 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 33 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.