Question

Can someone help me?

Answer 1

The answer for number 19 is 5

Answer 2

18.
A line perpendicular to the x-axis is parallel to the y-axis.
That means it's a vertical line.
All points of a vertical line have the same x-coordinate.
For example, if a vertical line passes through point (1, 0), then the equation of the line is x = 1. All points on that line have x-coordinate 1, no matter what the y-coordinate is.
In this case, the vertical line passes through point (-10, 5), so the equation of the line is
x = -10.
Answer: A. x = -10

19.
f(x) = 2/3 x - 1

They want to know 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

Answer: f(9) = 5

20.
$\sqrt{128} =$

$= \sqrt{64 \times 2}$

$= \sqrt{64} \times \sqrt{2}$

$= 8 \times \sqrt{2}$

$= 8 \sqrt{2}$