Answer: 
Step-by-step explanation:
Given
The perimeter of one equilateral triangle is P
The lengths of the equilateral triangle are equal
Suppose x is the length of each side

i.e.

Answer:
14. congruent means "THE SAME" so it will be "A" because there all the same letter.
15. D
Answer:
not sure for the 1st one but pretty sure 2nd one is B
Step-by-step explanation:
Answer:
-7
Step-by-step explanation:
Let's try getting rid of the numbers to isolate the x.
Add x on both sides to get rid of the x on the right side and to get 2x on the left side. This leaves us with 15.3 + 2x = 1.3
Subtract 15.3 on both sides to get rid of the 15.3 on the left side.
This would leave us with 2x = -14
Divide 2 on both sides to isolate the x.
The answer is x = -7