Which polynomial represents the sum below?

(-x4 + 4x3 + 1) + (4x3 + x + 2)

a. -x4 + 4x6 + x + 3
b. x8 + 8x7 + x + 3
c. -x7 + 8x6 + x + 7
d. -x4 + 8x3 + x + 3

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.