Write 405,000 in scientific notation

What are the solutions to the equation 4x2+3x=24-x

The tuition costs, c, for a local community college are modeled by c(h) = 250 + 200h, where h represents the number of credit hours taken. the local state university has tuition costs, s, modeled by the function s(h) = 300 + 180h. how many credit hours will a student have to take for the two tuition costs to be equal? round the answer to the nearest tenth of an hour.

Which value would be a solution for x in the inequality 47-4x< 7