Question

Can someone help me?

Answer 1

18. A line perpendicular to the x-axis is a vertical line.

The equation of a vertical line is

x = k,

where k is the x-coordinate of every point on the line.
Since this vertical line goes through point (-10, 0.5), and this point has x-coordinate -10, then every point on the line has x-coordinate -10.
The equation is

x = -10

19.


`f(x) = (2)/(3)x - 1`

To find f(9), just replace x with 9 and evaluate the expression.


`f(9) = (2)/(3) * 9 - 1`


`f(9) = (18)/(3) - 1`


`f(9) = 6 - 1`


`f(9) = 5`

20.


`√(128) =`


`= √(64 * 2)`


`= √(64) * √(2)`


`= 8 * √(2)`


`= 8 √(2)`