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Answer:
[tex]f(x)=\left\{\begin{array}{cl}-x^2+11x-28&\text{for $4<x<7$}\\x^2-11x+28&\text{otherwise}\end{array}\right.[/tex]
Step-by-step explanation:
The absolute value function negates its contents when those contents are negative. Here, the quadratic factors as ...
x^2 -11x +28 = (x -4)(x -7)
so will be negative when the factors have different signs. That will be the case for 4 < x < 7.
The piecewise function can be written in 3 parts, one part for x ≤ 4, another part for 4 < x < 7, and the remaining part for 7 ≤ x. The function expressions for x ≤ 4 and 7 ≤ x are identical.
In the answer above, we chose to write it with the part where the quadratic is negated being defined on the appropriate interval, and using "otherwise" for the rest of the function. It is a little unconventional to do it this way, but it is more compact and completely defines the function.
