Mark knows that to use a number line to add intergers, you move right to add a positive number and left to add a negative number. he wonders if subtraction follows the same model and moves either left or right depending on what type number ( positive or negative.) is being subtracted.

if subtracting a negative number you move right but if subtracting a positive number you would move left

an altitude of 15,000 feet

step-by-step explanation:

x =±sqrt(1/3)

step-by-step explanation:

x+4/6x=1/x

multiply each side by 6x to get rid of the fractions

6x*(x+4/6x)=1/x*6x

distribute

6x^2 +4 = 6

subtract 4 from each side

6x^2 +4-4 = 6-4

6x^2 =2

divide by 6

6x^2/6 = 2/6

x^2 = 1/3

take the square root of each side

sqrt(x^2) = ±sqrt(1/3)

x =±sqrt(1/3)