Answer:
We know that:
If T = area of the triangle
and R = area of the rectangle:
I T - RI < 4.
Now, we know that:
T = 8*6/2 = 8*3 = 24
R = 4*(x - 4) = 4*x - 16
Then replacing those values, we can write:
I24 - (4*x - 16)I < 4
I40 - 4*xI < 4
Now let's solve it:
First we aim for the first value that is not a solutions, this is when:
I40 - 4*xI = 4
we can write this as:
40 - 4*x = +-4
The first extreme is:
40 - 4*x = +4
x = (40 - 4)/4 = 9
The other extreme is:
40 - 4*x = -4
x = (40 + 4)/4 = 11.
Then the set of solutions is: S = (9, 11)