The work of a student to solve a set of equations is shown:

equation a: y = 15 – 2z
equation b: 2y = 3 – 4z

step 1: –2(y) = –2(15 – 2z) [equation a is multiplied by –2.]
2y = 3 – 4z [equation b]
step 2: –2y = 15 – 2z [equation a in step 1 is simplified.]
2y = 3 – 4z [equation b]
step 3: 0 = 18 – 6z [equations in step 2 are added.]
step 4: 6z = 18
step 5: z = 3
in which step did the student first make an error?

step1
step 2
step 3
step 4

answer: 4 meters

step-by-step explanation: to you understand 2/3 better you can do 1 divided by 3 = . then multiply that by the 2 which is .66666666666666667 then you would do 6 x .66666666666666667 which is 4.      

hope this .

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)