{45x+6y=15-x+18y=11 is

Step-by-step explanation:

45x+6y=15

-x+18y = 11

let's use elimination, the other way is by substitution,  either way works but, it looks to me like elimination would be easy with the  'y'

3(45x+6y=15)

135x + 18y = 45 ( subtract  2nd eq.  from 1st )

-( -x+18y = 11 )

136x +0y =34

x = 34 /136

x = 1 /4

there is X

plug that back into either of the 1st or 2nd equations to solve for y

- 1/4 + 18 y = 11

18y = 11 1/4

18y = 45/4

y = 45/4 *  1/18

y = 45/ 72

the fractions seem  "difficult"  but that's just what the given problem finds

sent a message if you don't "get it"    :)

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)