Solving absolute-value equations and inequalities

G

Guest

Guest
is you have [x-7]=4 with the [] being absolute value ... do you leave the x in the brakets or the answer?
my son has [x]=11?
I think that this should end up with
x=11 or x=3??
We're both lost! :?
 
Hello, 4 little piggies mom!

Given: \(\displaystyle \;|x\,-\,7|\:=\:4\)

My son has \(\displaystyle |x|\,=\,11\)
I think that this should end up with : \(\displaystyle x=11\) or \(\displaystyle x=3\)
You're right, Mom!

\(\displaystyle |x\,-\,7|\,=\,4\) means two equations:

. . . . . \(\displaystyle x\,-\,7\:=\:4\;\;\Rightarrow\;\;x\,=\,11\)

and: \(\displaystyle \;x\,-\,7\:=\:\)-\(\displaystyle 4\;\;\Rightarrow\;\;x\,=\,3\)


Often, we can think of an absolute value as a <u>distance</u>.

\(\displaystyle |x\,-\,7|\:=\:4\:\) means: the distance from \(\displaystyle x\) to \(\displaystyle "7"\) is 4 units.

. . That is, find \(\displaystyle x\) which is 4 units from "7".

And we find two values: one is 11, the other is 3.
 
Top