Answer
Given the statement: In parallelogram ABCD, diagonals AC and BD intersects at point E.
Given that ABCD is a parallelogram.
As, we know that in a parallelogram diagonals bisect each other.
Since AC and BD intersect at E, and we get E is the mid point of both diagonals AC and BD.
⇒ BE = DE .....[1]
Substitute the given values of
and
in [1] we have;

Subtract
on both sides we get;

Simplify:

Subtract 10 on both sides we get;

or



equate these factors equal to zero we get;
(x-5) = 0 and (x+2) = 0
we have;
x = 5 and x = -2
Since, x cannot be negative.
So, x =5

Diagonals BD = BE + DE = 35 + 35 =70 units.
Therefore, the value of BD = 70 units.