It's going to be kind of crazy, but you need to use Pythagorean's Theorem for this. That will look like this:

. FOIL out the left side to get

. FOIL out the first of the 2 expressions on the right to get

, and the second of the 2 to get 4x. Our equation now looks like this:

. Combine like terms to get an equation that still has square roots in it that we have to deal with:

and

. We will square both sides to get rid of the square root sign.

. This is a polynomial now that can be factored to solve for x. Bring the 2x over by subtraction and set the polynomial equal to 0.

. Factor out an x, leaving us with x(x-2)=0. That means that x = 0 or x - 2 = 0 and x = 2. Of course if we are solving for the length of a side we know it can't have a side length of 0, so it must have a side length that is a multiple of 2. x = 2
Answer:
C.1/4 the pqr is the prime of factor by negative comma 1
Answer: The length of BC is 7
Step-by-step explanation: Assuming the lengths of the opposite sides of the quadrilateral are congruent, then
AB=DC and
AD=BC
Inputting the values of AB, DC and AD as given in the question:
x + 8 = 3x ...(1)
x + 3=? ...(2)
We have to solve for the value of x to get the actual lengths and thus ascertain BD.
From equation (1):
8 = 3x - x
8 = 2x
8/2 = x
Therefore, x = 4.
If x = 4 then equation(2) would be
4 + 3= 7.
Hence, the actual lengths of the quadrilateral are:
AB = 4 + 8. DC = 3(4)
=12. =12.
AD = 4 + 3. AD = BC
= 7. Therefore, BC = 7.
Hence, it is confirmed that quadrilateral ABCD is a parallelogram since both the opposite sides are proven to be congruent.
Answer:
Step-by-step explanation: