Math experts! i need help?

Question

please solve and show work (and explain if you want best answer because i don't understand how to do this and the "|" symbols in math)

|7x-4y |-| -y| for x= -4,y =8

Answer 1

answer is 45 as

whatever you have in"|" make it postive like

|-5|=5

|5|=5

|-109|=109

so

|7(-4)- 4(8)|-|-8|

|-28-32|-|-8|

|-60|-|-8|

60-8

52

Answer 2

The l symbol means absolute value, which pretty much means turn the number in the l positive. so l-4l=4 and l5l =5 Now for the problem

l7x-4yl-l-yl

l7(-4)-4(8)l-l-8l

l-28-32l-l-8l

l-60l-l-8l

60-8

52  

Answer 3

how this symbol work?well if we have IxI=p then x=p if x>=0 and -x=p if x=<0.

I7(-4)-4(8)I-8=52