What is the sign of the product of two numbers with opposite signs

Which graph shows a function with a range of all real numbers greater than or equal to -1

The verbal translation for the difference of m and 7 increased by 15

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days