Your given question is unclear.
-2a-9=6a+15
Move 6a to the other side. Sign changs from +6a to -6a.
-2a-6a-9=6a-6a+15
-2a-6a-9=15
-8a-9=15
Move -9 to the other side. Sign changes from -9 to +9.
-8a-9+9=15+9
-8a=15+9
-8a=24
Divide both sides by -8
-8a/-8=24/-8
a=-3
Answer: a=-3
Using the midpoint formula, the coordinates of the intersection of the diagonals of the parallelogram is: (1, 2.5).
<h3>What are Diagonals of a Parallelogram?</h3>
The diagonals of a parallelogram bisect each other, therefore, the coordinates of their intersection can be determined using the midpoint formula, which is:
.
A diagonal is XZ.
X(2, 5) = (x1, y1)
Z(0, 0) = (x2, y2)
Plug in the values

= (1, 2.5).
Learn more about the diagonals of a parallelogram on:
brainly.com/question/12167853
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-3x + is greater than or equal to 35
hope this helps!