The standard form of a line:

We have the equation of a line in the slope-point form:
use distributive property
add 3 to both sides
multiply both sides by 2
subtract x from both sides
change the signs

Answer:
y= -2x-7
Step-by-step explanation:
point-slope: y-y1=m(x-x1)
y-3=-2(x-5)
y-3=-2x-10
y=-2x-7
39 meters in 3 minutes means 13 meters each minute and 26 meters in two minutes. Multiply by 1,000 to convert it into 26000 millimeters.
They gave you a set of numbers that you replace the variable x in the equation to see if it gives a correct answer so just do exactly that.
6 + 2x = 24
6 + 2(6) = 24
6 + 12 = 24
18 = 24 so incorrect. both sides are not equal to each other.
6 + 2x = 24
6 + 2(9) = 24
6 + 18 = 24
24 = 24 so correct. both sides are equal to each other.
6 + 2x = 24
6 + 2(15) = 24
6 + 30 = 24
36 = 24 so incorrect. both sides are not equal to each other.
6 + 2x = 24
6 + 2(16) = 24
6 + 32 = 24
38 = 24 so incorrect. both sides are not equal to each other.
so your answer is b) 9