The sum of the angles of a triangle is 180º.
We have three angles:
∠yxz=3x+5
∠xzy=180º-(8x-14)
∠xyz=4x
Therefore:
(3x+5º) + [180º-(8x-14º)]+(4x)=180º
3x-8x+4x=180º-5º-14º-180º
-x=-19º
x=19º
∠yxz=3x+5º =3(19º)+5º=62º
∠xzy=180º-(8x-14)=180º-(8(19º)-14)=42º
∠xyz=4x=4(19º)=76º
Answer: m∠yxz= 62º.
Answer:
(a) 
Step-by-step explanation:
The question is incomplete. (See comment for complete question).
From the completed question, we have:

--- number of pyramids
Required
An expression for the area of the base
The total base length of the pyramid represents the perimeter of the base.
And since the base is a square, then the following relationship exist.

Where L represents the length of each side.
This gives

Make L the subject

The area of the base is then calculated as:


8-9r is the answer to this