Why must every polynomial equation with real coefficients of degree 3 have at least one real root?

What is r i 4.5+10r=-6.5 with work pls

Find the rate of change for the situation.you run 7 miles in one hour and 21 miles in three hours.

Aliter of water contains about 3.35 x 10^25 molecules. a certain river discharges about 2.9x 10^8 l of water every second. about how many molecules does the river discharge every minute? write your answer in scientific notation