-5 is on the left side of zero (negative) and 5 is on the right side of zero (positive). So, 5 is the answer...
Yes. If the diagonals bisect the angles, the quadrilateral is always a parallelogram, specifically, a rhombus.
Consider quadrilateral ABCD. If diagonal AC bisects angles A and C, then ΔACB is congruent to ΔACD (ASA). Hence AB=AD and BC=CD (CPCTC).
Likewise, if diagonal BD bisects angles B and D, triangles BDA and BDC are congruent, thus AB=BC and AD=CD. (CPCTC again). Now, we have AB=BC=CD=AD, so the figure is a rhombus, hence a parallelogram.
and
so

and you rationalize denominator by multiplying numerator and denominatr by
so that gives--

Your answer is 
First, you plug your given values in. Since x is 1.5, it will be multiples by 2x to get 3.2. Since y is -3, it will be added to 1 to get -2. Finally, the two are multiplied together to get -6.4 if I am correct.
Answer: Choice A

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Explanation:
The pythagorean theorem is 
The value of c is always the longest side, aka hypotenuse.
The order of 'a' and b doesn't matter.
So a = 14, b = 48, c = 50
We have 
We also have 
Both sides result in 2500 which proves that
is a true statement. Therefore, we do have a right triangle.