Select the expressions that are equivalent to 7a+4a.

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

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class

What effect would doubling all the dimensions of a triangular pyramid have on the volume of the pyramid? explain your reasoning.