Hello!! Please help me solve the question, could you please also tell me which calculator we can use? Thank you

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

Similarly fie each expression 18,19,20

Y=x+2 4x+3y= -36 system of equation