Evaluate
where
(Sorry I can't get the LaTex for piecewise to work properly, hope it's not too hard to read)
=
=
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I believe the correct answer is -2 + 7 = 5.
If you draw the function it must be clear there's much more area under the x-axis than over it, so the integral will be negative:
Now, if you were asked to evaluate the (geometrical) AREA between the graph of the function and the x-axis then you have to change the sign of the second integral to make it positive and then the area is 9.
Tonio