2times the sum of a number and 8 is equal to the difference of 10 and that number find the number

Abcd is a parallelogram. the diagram is not drawn to scale. if m

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

I’m really confused and need to learn this