Sarah has a coupon for an oil change with synthetic oil for $49.95. She can buy 5 quarts of synthetic oil, which is what her car needs, for $37.54 and an oil filter for $9.47. How much can she save by doing the oil change herself

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

Solve the equation by completing the square. x^2+2x=17

If the scale factor between two circles is 2x/5y what is the ratio of their areas?