Answer:
x = -1
Explanation:
You want to find the value(s) of x that satisfy the equation |x-2| = |4+x|.
Domains
The behavior of each absolute value function changes at the point where its argument is zero. For this equation, that will be two points:
x -2 = 0 ⇒ x = 2
x +4 = 0 ⇒ x = -4
These two points on the number line divide the domain of the equation into three parts:
The behavior of the equation will be different in those three domains.
x < -4
In this domain, both absolute value functions negate their arguments. That means the equation is equivalent to ...
-(x -2) = -(4 +x)
2 = -4 . . . . . . . . . . add x to both sides
This has no solutions: there are no values of x that will make this true.
-4 ≤ x < 2
In this domain, the absolute value function on the left negates its argument, so the equation is equivalent to ...
-(x -2) = (4 +x)
-2 = 2x . . . . . . . . . add x-4 to both sides
-1 = x . . . . . . . . . divide by 2
This value of x is in the domain, so represents a solution to the equation.
x = -1
2 ≤ x
In this domain, neither absolute value function negates its argument, so the equation is equivalent to ...
x -2 = 4 +x
-2 = 4 . . . . . . . subtract x
This has no solutions: there are no values of x that will make this true.
The given equation has one solution: x = -1.
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Additional comment
When solving an equation like this graphically, it is often useful to put it in the form f(x) = 0. We can obtain that form by defining ...
f(x) = |x -2| -|4 +x|
The graph of this is attached. The only solution is where f(x) = 0, at x = -1.
Note that the function is parallel to the x-axis outside of the middle domain, so will not have any x-intercepts in those regions.