Which of the following differences could not give a distance between two points on a number line? Explain why.

(1) 19-7
(3) -12 -(-7)
(2) -3-(-18)
(4) 14-(-6)

Choice: (3) -12 -(-7)

Step-by-step explanation:

The distance between two points is by definition a positive number. If we wanted to know the distance between points 5 and 8, we should use the absolute value of the difference:

d=|5-8|=8-5=3

The same applies to negative points like -2 and -7:

d=|-2+7|=|2-7|=7-2=5

The only choice that does not result in a positive distance is (3) because

-12-(-7)=-12+7=-5

Thus this is not a distance between two points on a number line.

Choice: (3) -12 -(-7)

16

step-by-step explanation:

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x