My calculus assignment is asking this: If 4x, simplify the expression by removing the absolute sign. abs(4 - x) = ? It is asking for only a single definite answer. What could this be? I really don't understand.
Follow Math Help Forum on Facebook and Google+
Using the definition of the absolute value $\displaystyle |4-x|=4-x \ \ \ \mbox{if} \ \ 4-x>0$ $\displaystyle |4-x|=-(4-x) \ \ \mbox{if} \ \ 4-x<0$ Since $\displaystyle 4<x\Rightarrow 4-x<0$ $\displaystyle \Rightarrow |4-x|=-(4-x)=x-4$
Slightly more succinctly, if 4< x, then 0< x- 4, 0> 4- x.
View Tag Cloud