Answer:
The diagonals bisect each other.
Step-by-step explanation:
Not all diagonals of a parallelogram are equal.
The only quadrilaterals with all four sides being congruent are rhombus and squares so parallelogram is wrong.
The diagonals of a parallelogram bisect each other.
The diagonals of a parallelogram are only perpendicular when it is a square.
How to solve:

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Write all numerators above the least common denominator which is 24 in this case.

Subtract the numbers

Alternate form: 0.458333
The final, simplified, fraction answer is:
Use BODMAS or BIDMAS (Brackets, over Indices, Division, Multiplication, Addition, the Subtraction, this tells you which order to do things in)
As you cant do √10 in the brackets you do the indices, so (√10)³
Split this up to make it easier
(√10)³= √10 x √10 x √10 = 10√10
You the multiply this by 9
9 x 10√10 = 90√10
then multiply by 5
5 x 90√10 = 450√10 = 1423.024947 (using calculator)
It's hard to read your picture
But if your equation is
(-3)^2 + (-2)^3
then its:
-3*-3 + -2*-2*-2 = -9 - 8 = -17