Select all the expressions that cannot be factored using intergal coefficients and intergal constants
a. x^2 + 5x + 3
b. 25 - 20x + 4x^2
c. -2x^2 + 7x - 3
d. 2x^2 - 5x + 4

Volume of a cylinder with a radius of 13 in and height of 30 in

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?

Acertain volume of water contains 100000 hydrogen atoms and 50,000 oxygen atoms how many hydrogen atoms are in a volume of water containing 4 million oxygen atoms