Pls help me with these question pls?

Number one is only a function

Step-by-step explanation:

A function has all different x values, but if there are two of the same x values with different y values, that is not a function. It’s okay if there are two do the same x values- they just have to have the same y values.

Number one has all different x values

Number two has an x value with two different y values, therefore it is not a function

Number 3 has two of the same x values but with different y values, so it’s not a function

Number four is not a function because of the vertical line test. You pick a point on the line and draw a vertical line all the way through the line. If that point passes through any other points, that it is not a function. Number four doesn’t pass the vertical line test, so it’s not a function.

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1

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)