Find the missing side x:

Probably 5

Step-by-step explanation:

This is an extremely confusing question.  Whoever wrote it most likely had a typo.

The little box in the corner of the triangle means that is 90 degrees. if that is the case, this is a simple question:

Apply pythagorean theorem (a^2 + b^2 = c^2)

In this case:

3^2 + 4^2 = x^2

x^2 = 25

x=5.

HOWEVER: the two given angles are 60 degrees and 50 degrees.

Which does not work. It creates an impossible triangle.

Option D

Step-by-step explanation:

The given expression is x² + 8x + 15 = 0

We have to solve it further to transform into the form ( x - p )² = q

x² + 8x + 15 = 0

[ x² + 8x + 15 ] + 1 = 0 + 1

x² + 8x + 16 = 1

( x + 4 )² = 1

Option D is the answer.