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[SOLVED] creating an absolute value equation from an inequallity

karush

Well-known member
Jan 31, 2012
2,771
if you are given \(\displaystyle -6 \leq x \leq 14\)

from this how do you create an abs equation like \(\displaystyle |x-4| \leq 10\)

k
 

Chris L T521

Well-known member
Staff member
Jan 26, 2012
995
Re: creating an abs equation

if you are given \(\displaystyle -6 \leq x \leq 14\)

from this how do you create an abs equation like \(\displaystyle |x-4| \leq 10\)

k
Note that we can express the absolute value in terms of an inequality: $|y|\leq c \iff -c \leq y \leq c$.

Now, note that if we subtract 4 from each piece of $-6\leq x\leq 14$, we get $-10\leq x-4 \leq 10$. Thus, by what I mentioned in the first line, this means that $|x-4|\leq 10$.

Does this clarify things?
 

Plato

Well-known member
MHB Math Helper
Jan 27, 2012
196
Re: creating an abs equation

if you are given \(\displaystyle -6 \leq x \leq 14\)
from this how do you create an abs equation like \(\displaystyle |x-4| \leq 10\)
[tex]a \le x \le b[/tex] converts to [tex]\left| {x - \frac{{a + b}}{2}} \right| \le \frac{{b - a}}{2}[/tex].

Think of the mid-point of [tex][a,b][/tex] as well as the radius.