A taxpayer is allowed one-seventh of his income tax free, and pays sixteen percent tax on the reminder. If he pays five hundred and forty dollars tax, what is his tax free income

An equation of the line tangent to y=x^3+3x^2+2 at its point of inflection is

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

Trent wants to buy 2 packs of trading cards for 3 dollars each. the trading card packs that trent normally buys tend to come in packs of 6, 10, 12, or 15 cards. after selecting 2 packs, trent found that the first pack of cards cost 25 cents per card, and the second pack cost 30 cents per card. trent uses this information to write the equations below in order to compare c, the number of cards in each pack.