|-13|-|13|=-13-13=-26

Question

Describe and correct error

Answer 1

Veronica,

           The absolute value function is defined as |x|=x when x≥0 and -x when x<0. When you graph it it looks like a V with the vertex at the origin.

          Now when you apply the definition of |x| to the problem we have |-13| in this case x=-13 so |x|=13 and the next term is just 13 so the difference is 13-13=0.

 

          Hope this was helpful

Jim

Answer 2

Hi Veronica--

 

Remember that absolute values are always positive. (Think of an absolute value as a distance. If you walk 5 miles, then you walk back home in the opposite direction, you still walked those 5 miles twice--once there, and once back.)

 

Make a number line, with 0 at the midpoint, -26 at the far left, and 26 at the far right. When you put -13 on there, you'll see that even though it is negative, you still had to take 13 actual steps from zero to get there, so its absolute value is positive.

 

Knowing that, re-write your equation accounting for the fact that everything inside a pair of absolute-value bars has a positive value.

 

You may be able to solve from there, but let me know if you need more...

 

Matt in NY